C# Certification

Question 1

Suppose you are developing an application which stores a user’s browser history. Which collection class will help to retrieve information of the last visited page?

Answer 1

Last visited (LIFO= Stack)

Answer = Stack

Question 2

The following code is boxed into object o.

double d = 34.5;
object o = d;

You are asked to cast “object o” into “int”.

Answer 2

The object needs to be cast to double
Because it is a decimal value need to cast to float
Finally cast to int

Answer = int i = (int)(float)(double)o;

Question 3

You are developing a game that allows players to collect from 0 through 1000 coins. You are creating a method that will be used in the game. The method includes the following code. (Line numbers are included for reference only)

01 public string FormatCoins(string name, int coins)
02 {
03
04 }

The method must meet he following requirements:

1. Return a string that includes the player name and the number of coins
2. Display the number of coins without leading zeros if the number is 1 or greater
3. Display the number of coins as a single 0 if the number is zero

You need to ensure that the method meets the requirements. Which code segment should you insert at line 03

Answer 3

Format specifier D formats integer digits with optional negative sign.

Answer = string.Format($”Player {name}, collected {coins:D3} coins”);

Question 4

How do you encapsulate an array of integers into an indexer?

Answer 4

private int[] array;

public int this[int index]
{
  get {return array[index];}
  set { array[index] = value;}
}

Question 5

Is the following method “Display” considered to be overloaded?

class Person
{
  public void Display()
 {
 }

public int Display()
{
}
}

Answer 5

No

Overloading refers to different parameter types. The display method has different return types.

Question 6

Suppose you’re creating a class named Player. The class exposes a string property named HitSpeed. Here is the code snippet of player class.

01 class Player
02 {
03   public int HitSpeed
04   {
05     get;
06     set;
07   }
08 }

The HitSpeed property must meet the following requirements:

1. The value must be accessed by code within the Player class
2. The value must be accessed to derived classes of Player
3. The value must be modified only by code within the Player class.

You need to ensure that the implementation of the EmployeeType property meets the requirements. Which code segment you should replace at line 05, and 06?

Answer 6

protected get;

private set;

Question 7

Suppose you are developing an application. The application has two classes named Player and Person.

The Player class must meet the following requirements

1. It must inherit from the Person class
2. It must not be inheritable by other classes in the application.

Which code segment should you use?

Answer 7

sealed class Player : Person
{

}

Question 8

Suppose you are developing an application that includes the following code segment.

interface ICricket
{
  void Play();
}

interface IFootball
{
}

You need to implement both Play() methods in a derived class named Player that uses the Play() method of each interface.

Answer 8

class Player : ICricket, IFootball
{
  // Both ICricket and IFootball have play methods
  // Must be declared explicitly
  void ICricket.Play()
  {
  }
  void IFootball.Play()
  {
  }
}

Player player = new Player();
( (ICricket)player ).Play();
( (IFootball)player).Play();

Question 9

Which type cannot be instantiated?
A enum type
B static type
C class type
D System.Object type

Answer 9

B. Static type

Question 10

Which operator is used to get instance data inside type definition?

Answer 10

this

Question 11

What is the code segment for defining implicit type conversion for a Person class?

Answer 11

class Person
{
  public string name;
  public int age;

public static implicit operator Person(string n)
{
Person person = new Person{age=0, name=n};
return person;
}

Question 12

Which operator is used to compare types?

A) as
B) is
C) this
D) ?

Answer 12

B) is

Question 13

Suppose you are developing an application that saves age values in integers

int age = 22;

You are asked to provide the right code snippet for defining the extension method for age.

Answer 13

static class Extension
{
 public static void ExtensionMethod(this int i)
 {

}
}

Question 14

Which jump statement will you use to start the next iteration while skipping the current iteration of loop?

Answer 14

Continue

Question 15

You need to use null-coalescing operator to make sue “name” variable must have a value not null.

What is the right way to use null-coalescing operator in C#?

Answer 15

string name = n??”No Name”;

Question 16

You are developing an application that saves user’s information. The application includes the following code segment (line numbers included for reference).

01 public bool IsNull(string name)
02 {
03 return true;
04 }

You need to evaluate whether a name is null

What code segment should be inserted at line 03.

Answer 16

I would do this….

return string.IsNullOrWhiteSpace(name) ? false: true;

or

return name==null?false: true;

Question 17

Suppose you are implementing a method name “Show” that will be able to take an unlimited number of int arguments. How are you going to define its method signature.

Answer 17

void Show(params int[] arg)

Question 18

Which of the following methods help us to convert string type data into integers?

Select any two

A) Convert.toInt32();
B) Convert.Int32();
C) int.parse();
D) parse.int();

Answer 18

A) Convert.toInt32()

C) int.parse()

Question 19

What collections stores values in Key, Value pairs?

Answer 19

Dictionary
SortedList
HashTable

Question 20

To control how objects are compared, what interface is implemented

Answer 20

IComparable

Question 21

Last In, First Out data structures are represented as?

Answer 21

Stack

Question 22

First In, First Out structures are represented as?

Answer 22

Queue

Question 23

When are generic collection classes appropriate?

Answer 23

When all objects are of the same type

Question 24

What namespace is inherited by the following data structures?

Dictionary
List
Queue
Stack
SortedList

Answer 24

System.Collections.Generic

Question 25

What namespace is inherited by the following data structures?

ArrayList
HashTable
Queue
Stack
SortedList

Answer 25

System.Collections

Question 26

Arrays inherit from what namespace?

Answer 26

System.Array

Question 27

What object used with a DataSet is used to add, update or delete records from a database?

Answer 27

DataAdapter

Question 28

How is a dataset populated with data?

Answer 28

using the DataAdapter

Question 29

What is a DataSet

Answer 29

A disconnected resultset that contains one or more data tables

Question 30

What method returns the data represented as XML

Answer 30

ExecuteXMLReader

Question 31

What method is used to return a single value from a database such as when a query returns a Sum or Count

Answer 31

ExecuteScalar

Question 32

What object is a read-only, forward-only cursor connected to the database?

Answer 32

DBDataReader

Question 33

What method is used to execute non-result returning queries such as Insert, Update or Delete

Answer 33

ExecuteNonQuery

Question 34

What object is used to call a stored procedure or execute a dynamic SQL statement?

Answer 34

The Command object

Question 35

What is ADO.Net?

Answer 35

A set of classes used to execute commands on a database

Question 36

An ORM tool that masks the syntax for using ADO.Net to communicate with a database is referred to as?

Answer 36

Entity Framework

Question 37

Classes are representative of what within Entity Framework Model

Answer 37

objects in the database

Question 38

Within the Entity Framework Model, stored procedures are represented as what?

Answer 38

Methods

Question 39

How are parameters passed by WCF Data Services to query a database?

Answer 39

By passing the parameters within the URL query string

Question 40

What data formats are returned by WCF Data Services?

Answer 40

OData Adam

JSON

Question 41

What protocol is used by WCF Data Services?

Answer 41

OData

Question 42

What purpose does the await command serve?

Answer 42

Kicks off the method and returns processing to the calling method until the method completes

Question 43

The async keyword must modify what in order to use the await keyword?

Answer 43

The method signature

Question 44

In C# 5.0 and later, what keywords are used to perform asynchronous operations?

Answer 44

asynch & await

Question 45

What classes are used to read and write string data

Answer 45

StringWriter

StringReader

Question 46

Name three methods used by StreamReader to get the contents of a file.

Answer 46

Character by Character
Line by Line
Entire File at once

Question 47

What is the default character encoding for StreamReader and StreamWriter

Answer 47

UTF-8

Question 48

What classes are used for reading and writing characters by using an encoded value to convert the characters to and from bytes?

Answer 48

StreamReader

StreamWriter

Question 49

What classes are used for reading or writing binary values?

Answer 49

BinaryReader

BinaryWriter

Question 50

What object is used to represent the contents of a file in memory and can be used to write data or read data from a file.

Answer 50

Stream

Question 51

What objects are used to determine properties of a file and also performs operations on a file

Answer 51

File and FileInfo

Question 52

In LINQ, what is an outer sequence?

Answer 52

The sequence calling the Join method

Question 53

A feature of LINQ that uses extension methods on types that implement the IEnumerable or IQueryable interface to query the data is a ..?

Answer 53

Method based query.

Question 54

LINQ statements executed in a where clause for a query expression is called it’s..?

Answer 54

Predicate

Question 55

LINQ statements that select a subset of properties from a type that creates a new anonymous type is referred to as ?

Answer 55

Projection

Question 56

A feautre of LINQ that enables you to query any type that implements the IEnumerable or IQueryable interface is called?

Answer 56

Query expression

Question 57

A set of features that extends query capabilities to C# is called?

Answer 57

Language Integrated Query
or
LINQ

Question 58

In LINQ, what is an inner sequence?

Answer 58

When using a method based join, the sequence passed to the join as a parameter.

Question 59

A variable that has its type determined by the expression on the right side of the initialization statement and using the keyword var is .. .?

Answer 59

Implicitly typed

Question 60

What operator is the”goes to” or “such that” operator?

Answer 60

=>

Used primarily in lambda expressions

Question 61

Execution of a LINQ query is deferred until the result is enumerated.

This is referred to as ?

Answer 61

Deferred execution

Question 62

Define a composite key

Answer 62

Contains multple properties that are needed to complete a join.

Question 63

A type created with read-only properties without having to write the code to declare the class is referred to as an….?

Answer 63

Anonymous type

Question 64

What class is used in a LINQ to XML query to return the result of a query in XML?

Answer 64

XElement

Question 65

What LINQ method allows you to return a distinct list of elements from a sequence?

Answer 65

Distinct

Question 66

What LINQ method allows you to return a limited number of elements from a sequence.

Answer 66

Take

Question 67

What LINQ method allows you to skip a specific number of elements in a sequence?

Answer 67

Skip

Question 68

In LINQ, how are two sequences concatenated?

Answer 68

Concat

Question 69

When using method based LINQ queries, how are out joins formed?

Answer 69

GroupJoin

Question 70

In LINQ, what is the purpose of the SelectMany method?

Answer 70

To flatten two sequences into one result, similar to join.

Question 71

Which LINQ query uses lambda expressions as parameters to methods?

Answer 71

Method based queries

Question 72

What is the difference between method based queries and query expressions?

Answer 72

Syntax, no functional difference.

Question 73

In LINQ, a group by clause returns what data type?

Answer 73

IGrouping

Question 74

How is a LINQ composit key formed?

Answer 74

By specifying an anonymous type in the join clause

Question 75

In LINQ, how are outer joins formed?

Answer 75

1) Include an INTO clause in your join

2) Call the Default ifEmpty to set properties when no match is found.

Question 76

What keyword is used to join properties in LINQ?

Answer 76

Equals

Question 77

Define projection

Answer 77

Creating a custom type in a select clause of a query expression using a limited number of properties from the original object.

Question 78

What query expression clause is used to sort the results on one or more properties?

Answer 78

OrderBy

Question 79

How are multiple where clauses implemented using LINQ?

Answer 79

By using the && operator

Question 80

Define the predicate in LINQ

Answer 80

All code contained within the Where clause

Question 81

How are joins evaluated in LINQ queries?

Answer 81

Joins are always equivalence based

Question 82

How is the execution of a LINQ query forced?

Answer 82

By using any of the aggregate functions or populating a list or array using toList() or toArray()

Question 83

When does execution of a LINQ query occur?

Answer 83

When the result is enumerated

Question 84

Define a LINQ clause

Answer 84

A query expression containing Select, GroupBy, Where or joins

Question 85

By convention, the results of a LINQ query are stored where?

Answer 85

To a variable of type var, allowing the result to be implicitly typed.

Question 86

What object can be queried by LINQ?

Answer 86

Any object that implements IEnumerable or IQueryable

Question 87

Define the correct order of keywords for a LINQ query expression.

Answer 87

from…
where …
select …

Question 88

Define a statement that returns the count of all even numbers

Answer 88

var count = myNumbers.Where(i => i %2 == 0)
                                         .Count()

Question 89

Define a statement that groups a sequence by the State property

Answer 89

var states = myStates.GroupBy(s => s.name);

Question 90

Define a statement that creates an anonymous type

Answer 90

.Select( new {h.city, h.state})

Question 91

What two keywords must you use in a join clause to create an outer join?

Answer 91

into

DefaultIfEmpty

Question 92

Define a clause that joins two sequences on the stateId property

Answer 92

on e.stateId equals s.stateId

Question 93

Define a join clause that uses a composite key

Answer 93

on new {City = e.City, State = e.State}
equals
new {City = h.City, State = h.State}

Question 94

Define a LINQ clause that orders by state and then by city

Answer 94

Orderby h.state, h.city

Question 95

Define a WHERE clause that returns all integers between 10 and 20

Answer 95

Where i >= 10 && i <= 20

Question 96

Define the extension LINQ method used to find the first item in a sequence

Answer 96

First or Take

Question 97

Define how to find the minimum value in a sequence

Answer 97

(from i in myArray

selecti).Min()

Question 98

Given:
var result = from i in my Array
order by i
select i;

foreach(int i in result)
{
   // Do something
}

Where is the LINQ query executed?

Answer 98

When enumerating the foreach statement

Question 99

Define a WHERE clause that selects all integers in a myList object that are even number given

from i in myList

Answer 99

Where i % 2 == 0;

Question 100

Name two methods of performing customized serialization

Answer 100

Attributes (the preferred method)

Implement Iserializable

Question 101

What class is used to perform binary serialization.

Answer 101

BinaryFormatter

Question 102

XML serialization is performed by what class?

Answer 102

XMLSerializer

Question 103

What class is used to perform JSON serialization

Answer 103

DataContractJsonSerializer

Question 104

What is serialization?

Answer 104

The process of transforming an objects data to persisted storage or to transfer the object from one domain to another

Question 105

A set of classes in the .NET framework that enables you to convert to a database, retrieve data, execute stored procedures, add, update, or delete records in a table called?

Answer 105

ADO.NET

Question 106

What is the object relationship mapping tool that provides a graphical interface that generates code to perform operations against a db using ADO?

Answer 106

ADO.NET Entity Framework

Question 107

The most basic type used to store a set of data is called?

Answer 107

Array

Question 108

What is the role of the keyword async?

Answer 108

Indicates that the method, lambda expression, or anonymous method is asynchronous

Question 109

What keyword suspends the execution of a method until the awaited task completes?

Answer 109

await

Question 110

The process of converting a reference type to a value type is called?

Answer 110

unboxing

Question 111

What is boxing?

Answer 111

The process of converting a value type to a reference type

Question 112

What is a collection?

Answer 112

A generic term encompassing lists, dictionaries, queues, stacks, hash tables and other objects that contain sets of data.

Question 113

The object in ADO.NET that allows you to open and execute commands against a database is called?

Answer 113

A connection object.

Question 114

What is the IComparable interface?

Answer 114

Implements an interface that can be sorted when used in a collection or array.

Question 115

A method that is used when referencing an element in an array or collection by using square brackets[] and it’s index is called?

Answer 115

indexer

Question 116

What is JSON?

Answer 116

JavaScript Object Notation

A lightweight data-interchange format

Question 117

A computer software term for tools that convert data between type systems using an object oriented programming language is called?

Answer 117

ORM

Object Relational Mapping

Question 118

The XML representation of data returned from an OData query is called?

Answer 118

OData ATOM

Question 119

What is OData?

Answer 119

Open Data Protocoal

A web protocol for querying and updating data over the intranet or internet

Question 120

Creating a new copy of an object that copies all value types and copies object references for reference types is called a ?

Answer 120

shallow copy

Question 121

The process of converting an object into a stream of bytes that can be stored or transmitted is called?

Answer 121

serialization

Question 122

Define stream.

Answer 122

An abstract class that provides a generic view of a sequence of bytes.

Question 123

What is a T4 template?

Answer 123

A file that contains text blocks and control statements that enable you to generate a code file.

Question 124

What enables you to use OData to expose and consume data over the web or intranet?

Answer 124

WCF Data Services

WCF=(Windows Communication Foundation)

Question 125

You are working with a large group of family objects. You need to remove all duplicates and then group them by last name.

Which collections should you use?

Answer 125

List to hold the original objects

Dictionary to remove duplicates and create key of last names.

Question 126

You are using a queue and you want to add a new item.

Which method do you use?

Answer 126

Enqueue

Question 127

You want to store a group of orders and make sure that a user can easily select an order by it’s order number.

Which collection do you use?

Answer 127

Dictionary

Question 128

What must be implemented when creating custom collections?

Answer 128

Both IEnumerable and IEnumerable

Question 129

What collection stores values in memory as a last-in-last-out structure?

Answer 129

Stack, Stack

Question 130

What collection stores value in memory as a first-in-first-out structure?

Answer 130

Queue, Queue

Question 131

What collection stores unique items and offer set operations?

Answer 131

HashSet

Question 132

What is a dictionary?

Answer 132

A collection that stores and accesses items via key/value pairs.

Question 133

What is the most used collection?

Answer 133

List, List

Question 134

Define an Array

Answer 134

The most basic collection type which is constrained by a fixed size

Question 135

When given the opportunity to use the generic or non-generic collection, which is generally preferred?

Answer 135

Always use generic where possible.

Question 136

You want to serialize some data to XML, and you need to make sure that a certain property is NOT serialized.

Which attribute should you use?

Answer 136

XMLIgnore

Question 137

You are serializing some sensitive data to a binary format.

What should you use?

Answer 137

BinaryFormatter to put the data in binary format.

ISerializable to protect sensitive data.

Question 138

JSON text formatted files are created in .NET using what class?

Answer 138

DataContractJsonSerializer

Question 139

You need to store a large amount of data and you want to do this in the most optimal way.

What serializer should you use?

Answer 139

BinaryFormatter

Question 140

WCF serialization is performed using what class?

Answer 140

DataContractJsonSerializer

Question 141

How is binary serialization performed in .NET?

Answer 141

Using the BinaryFormatter class

Question 142

How is the XMLSerializer configured?

Answer 142

Through the use of attributes.

Question 143

What class handles XML serializtion?

Answer 143

XMLSerializer

Question 144

What is deserialization

Answer 144

Takes a series of bytes or a flat file and transforms it to an object

Question 145

What is serialization?

Answer 145

The process of transforming an object to a flat file or series of bytes

Question 146

Given query

var query = from p in myContext.Products
                    where p.price < 50
                    select p;
int numberOfItems = query.Count();
var products = query.ToList();

How can you improve performance?

Answer 146

Use paging to limit the number of items retrieved

And

Avoid hitting the database multiple times

Question 147

You are trying to use a LINQ query but receiving a compile error that the Where method cannot be found.

What steps should you take?

Answer 147

1. verify using System.Linq

2. Validate the datatype implements IEnumerable, IEnumerable

Question 148

You have a list of data you want to filter the dates to the current year and then select the highest date.

Create the query.

Answer 148

DateTime result = dates.Where( d => d.Year ==
DateTime.Now.Year)
.OrderByDescending( d=>d)
.FirstOrDefault();

Question 149

When are LINQ queries executed?

Answer 149

Not until they are first iterated, known as deferred execution.

Question 150

What is the primary function of LINQ?

Answer 150

To provide a uniform way of writing queries against multiple data stores.

Question 151

Which ADO.NET command objects’s property would you use when a query returns the sum of a column in a table?

Answer 151

ExecuteScalar

Question 152

Which property of an ADO.NET DataAdapter is used to insert records in a database?

Answer 152

InsertCommand

Question 153

Which method of a DataAdapter is used to populate a DataSet?

Answer 153

Fill

Question 154

Which ADO.NET object is fully traversable cursor and is disconnected from the database?

Answer 154

DataTable

Question 155

Which ADO.NET command object’s property would you use when a query returns the sum of a column in a table?

Answer 155

ExecuteScalar

Question 156

Which ADO.NET object is a forward-only cursor and is connected to the database while the cursor is open?

Answer 156

DBDataReader

Question 157

using ADO.NET Entity Framework how is a record updated in the database?

Answer 157

Category category = db.Categories.First( c =>
c.CategoryName = “alcohol”);

category. Description = “Happy Please”;
db. SaveCjhanges();

Question 158

Using ADO.NET Entity Framework, how is a record added to the database?

Answer 158

using(NorthwindsEntitities db = new NorthwindEntities())
{
  Category category = new Category()
  {
    category = "Alcohol",
    description = "beverage"
  }

db.Categories.Add(category);
db.SaveChanges();
}

Question 159

How are stored procedures represented in the ADO.NET Entity Framework?

Answer 159

A method is added to the model that is the same name as the stored procedure.

Question 160

When using the ADO.NET Entity Framework you create a model that represents the object in the databases.

What class does the model inherit from?

Answer 160

DBContext

Question 161

Which command object’s method would you use to execute a query that returns only one row and one column?

Answer 161

ExecuteScalar

Question 162

Which command object’s method would you use to execute a query that does not return any results?

Answer 162

ExecuteNonQuery

Question 163

Which properties of an ADO.NET command object must you set to execute a stored procedure?

Answer 163

CommandType
CommandText
Parameters

Question 164

Which ADO.NET object is used to connect to a database?

Answer 164

Connection

Question 165

Which collection would you use if you need to quickly find an element by its key rather than it’s index?

Answer 165

Dictionary
or
SortedList

Question 166

Which collection would you use if you need to process the items in the collection on a last-in, first-out order?

Answer 166

Stack, Stack

Question 167

Which collection would you use if you need to process the items in the collection on first-in, first-out order?

Answer 167

Queue, Queue

Question 168

If you create a custom class that is going to be used as elements in a List object and you want to use the Sort method of the List object to sort the elements in the array, what steps must you take?

Answer 168

1. Inherit from IComparable

2. Implement CompareTo()

Question 169

Which type should you use to store objects of different types but do no know how many elements you need at the time of creation?

Answer 169

ArrayList

Question 170

Which object does the variable mySet inherit from?

int[] mySet = new int[5];

Answer 170

System.Array

Question 171

Custom collections must inherit from which base class?

Answer 171

CollectionBase

Question 172

What is SSL?

Answer 172

Secure Socket Layer is a cryptographic protocol used for secure communication over the internet.

Question 173

Define secured hash algorithm

Answer 173

SHA is a family of cryptographic algorithms used to calculate hashes published by NIST

Question 174

What is the infrastructure required to handle digital certificates?

Answer 174

Public Key Infrastructure (PKI)

Question 175

A family of cryptographic algorithms used to provide data integrity and authenticity is called?

Answer 175

Message Authentication Code (MAC)

Question 176

What is the Just In Time (JIT) compiler?

Answer 176

A component of the .NET that transforms the IL into binary code that can be run on the target platform.

Question 177

The result of compiling a .NET application from source code is called the?

Answer 177

Intermediate Language (IL)

Question 178

A data array used by the encryption algorithm to encrypt the first data block is referred to as the?

Answer 178

Initialization Vector (IV)

Question 179

Describe hashing.

Answer 179

Used to map data structures of variable length to fixed size data structures.

Question 180

A data structure that holds items that share the same hash value is called?

Answer 180

Hash Bucket

Question 181

What is the Global Assembly Cache?

Answer 181

The GAC is a machine-wide code cache

Question 182

The process of decoding previously encrypted data so that it can be used by your application is?

Answer 182

Decryption

Question 183

The process of encoding data so that it cannot be read by an unauthorized person is called?

Answer 183

Encryption

Question 184

The practice and study of techniques for secure communication is called?

Answer 184

Cryptography

Question 185

A list of digital certificates that have been revoked for various reasons is referred to as?

Answer 185

Certificate Revocation List (CRL)

Question 186

Define the CLR

Answer 186

The Common Language Runtime is the component of the .NET Framework responsible for running .NET applications and managing the running environment.

Question 187

Define Certificate Stores

Answer 187

A special storage location on your computer, used to store encryption certificates

Question 188

What entity issues digital certificates?

Answer 188

Certificate Authority (CA)

Question 189

Define asymmetric encryption

Answer 189

A criptographic algorithm that uses two complimentary keys. One for encryption and one for decryption.

Question 190

What is an assembly?

Answer 190

An assembly is the unit of reuse, deployment, versioning and security.

Question 191

You need to process a large number of XML files ina scheduled service to extract some data.

Which class should you use?

Answer 191

Because data is only being extracted, use XmlReader

Question 192

You are planning to build an application that will use an object-oriented design. It will be used by multiple users at a time.

Which technology should you use?

Answer 192

An ORM such as Entity Framework

Question 193

You want to update a specific row in the database.

What commands are required?

Answer 193

1. SqlConnection to establish connection to database

2. SqlCommand to execute the query

Question 194

Name the four classes used to manipulate XML.

Answer 194

XmlReader
XmlWriter
XPathNavigator
XmlDocument

Question 195

Why should you use parameterized queries when performing CRUD operations?

Answer 195

To avoid Sql injection

Question 196

Under ADO.NET, how are connections made to the database?

Answer 196

Using the DBConnection object

Question 197

What is ADO.NET?

Answer 197

A provider model that enables you to connect to different types of databases.

Question 198

You are writing an application that will be deployed to western countries. It outputs user activity to a text file.

Which encoding should you use?

Answer 198

UTF-8

Question 199

You have built a complex calculation algorithm. It takes quite some time to complete and you want to make sure that your application remains responsive, what do you do?

Answer 199

Task.Run()

The process will run on a background thread

Question 200

You are creating a new file to store some log data. Each time a new log entry is necessary, you write a string to the file.

Which method should you use?

Answer 200

File.AppendText

Question 201

What namespace supports WebRequest and WebResponse?

Answer 201

System.Net

Question 202

What classes are used for performing network requests?

Answer 202

WebRequest

WebResponse

Question 203

What class implementation is used for dealing with files, network operations and other types of IO

Answer 203

Stream

Question 204

Define streams

Answer 204

An abstract method for working with a series of bytes

Question 205

What methods are available to create and parse file paths?

Answer 205

static Path class

Question 206

What methods are provided to work with files?

Answer 206

File

FileInfo

Question 207

How are folders manipulated programmatically?

Answer 207

Directory

DirectoryInfo

Question 208

How are drives manipulated programmatically?

Answer 208

Drive

DriveInfo

Question 209

Write code to decrypt an array called encryptedData that was encrypted by the current user and without using entropy

Answer 209

ProtectedData.Unprotect( encryptedData,
null,
DataProtectionScope.CurrentUser);

Question 210

What is a strong name assembly?

Answer 210

A signed assembly

Question 211

How can you deploy a private assembly?

Answer 211

By copying the file to the bin folder
or
Adding a reference to the assembly via Visual Studio

Question 212

How can you deploy a strong named assembly?

Answer 212

Run gacutil.exe
or
copy file to bin folder
or
create an installer

Question 213

Describe the components of a strong named assembly

Answer 213

Name
Version
Public Key Token
Culture
Processing Architecture

Question 214

Write a code snippet to encrypt an array called userData that can be decrypted by anyone logged in on the current machine without using any entropy.

Answer 214

ProtectedData.Protect(userData,
null,
DataProtectionScope.LocalMachine);

Question 215

Write a code snippet to calculate the secure hash of a byte array called userData using the SHA algorithm

Answer 215

sha.ComputeHash(userData);

Question 216

You are a developer at company xyz. You have been asked to implement a method to handle password encryption without offering the possibility to restore the password

What algorithm fits the requirement?

Answer 216

Hashing algorithm

Question 217

You are a developer at company xyz. You have been asked to implement a method to safely send data to another machine.

What kind of algorithm best fits the requirement?

Answer 217

Asymmetric algorithm

Question 218

You are a developer at company xyz. You have been asked to implement a method to safely save and restore data on the local machine.

What kind of algorithm best fits the requirements?

Answer 218

Symmetric algorithm.

Question 219

When is a MAC algorithm recommended?

Answer 219

To ensure both authenticity and integrity is required

Question 220

When is the hashing algorithm recommended?

Answer 220

When data integrity is the only requirement

Question 221

When is asymmetric encryption recommended?

Answer 221

If you do not have a way to send data securely

Question 222

When is symmetric encryption the best option?

Answer 222

IF you need to encrypt data locally or you have a secure way to distribute the encryption key.

Question 223

How is the encryptor/decryptor used?

Answer 223

Directly, using TransformFinalBlock or sending to CryptoStream

Question 224

How is symmetric encryption instantiated?

Answer 224

By calling
CreateEncryptor
CreateDecryptor

Question 225

What is required to perform symmetric encryption?

Answer 225

An initialization vector (IV) used to encryp the first block of data.

Question 226

Define symmetric encryption

Answer 226

Encryption based on a shared secret

Question 227

How many keys are used in asymmetric encryption?

Answer 227

Two

1. Private key
2. Public key

Question 228

Define asymmetric encryption

Answer 228

Based on a pair of complimentary keys. Data encrypted by one key can be decrypted by the other.

Question 229

Write a regular expression that matches license plate values that must include
three uppercase letters,
followed by a space and three digits,
or three digits followed by a space and three uppercase letters.

Answer 229

(^d{3} [A-Z] {3}$) | (^[A-Z]{3} \d{3}$)

Question 230

Write a regular expression that matches a username that must include between 6 and 16 letters, numbers and underscores

Answer 230

^[a-zA-Z0-9_]{6,16}$

Question 231

Write a regular expression matching the social security number format ###-##-#### where # is any digit.

Answer 231

^\d{3}-\d{2}-\d{4}$

Question 232

What method returns true if a regular expression matches a string?

Answer 232

Regex.IsMatch

Question 233

What is the best use of performance counters?

Answer 233

To determine how often a particular operation is occurring on the system as a whole.

Question 234

True or False

Whan an assertion fails in debug builds, the Debug.Assert method allows you halt, debug the program or continue running?

Answer 234

True

Question 235

True or False

The program must continue running even if a Debug.Assert method stops the program

Answer 235

True

Question 236

True or False

The Debug.Assert method is ignored in release builds

Answer 236

True

Question 237

What builds define the TRACE symbol?

Answer 237

Debug and Release

Question 238

What builds define the Debug symbol

Answer 238

Debug

Question 239

How can you prevent Visual Studio from creating a .pdb file?

Answer 239

Setting the value of PDB file type to “None”

Question 240

What file is required to debug a compiled executable?

Answer 240

.pdb file

Question 241

What statements are used to trace or log a program’s execution?

Answer 241

DEBUG
and
TRACE

Question 242

The process of making the program record key events in a log file is referred to as?

Answer 242

logging

Question 243

The process of instrumenting a program to track what is doing is referred to as ?

Answer 243

Tracing

Question 244

What method would you use to investigate bottlenecks in a program?

Answer 244

Use an automatic profiler

Question 245

What statement can be used to validate data as it moves through a program?

Answer 245

Debug.Assert

Question 246

How are preprocessor symbols disabled?

Answer 246

UNDEF

Question 247

What processor directives define preprocessor symbols?

Answer 247

DEFINE

Question 248

How can you determine what code is included in a program?

Answer 248

By using directives
#if
#elif
#else
#endif

Question 249

What is the purpose of the #line directive?

Answer 249

To change the line number or name of file reported as errors

Question 250

How are custom warnings and/or errors added to the error list?

Answer 250

by using
#warning
or
#error

Question 251

What is the syntax to create collapsible code regions?

Answer 251

#region
..
#endregion

Question 252

What is the syntax to disable a warning?

Answer 252

pragma warning disable

Question 253

What is the syntax to restore a warning?

Answer 253

pragma warning restore

Question 254

Where is the predefined constant TRACE defined?

Answer 254

In the debug and release builds

Question 255

Where is the predefined constant DEBUG defined?

Answer 255

In the debug builds

Question 256

Calls to DEBUG and TRACE are ignored if?

Answer 256

Both DEBUG and TRACE are not defined

Question 257

Useful DEBUG and TRACE methods include?

Answer 257

Assert
Fail
Flush
Indent
Unindent
Write
WriteIf
WriteLine
WriteLineIf

Question 258

When adding standard listeners to Debug and Trace objects, where are messages written to?

Answer 258

1. Output window
2. Event logs
3. Text files

Question 259

What file is used to debug a compiled executable?

Answer 259

.pdb

Question 260

What directives are used to implement tracing?

Answer 260

DEBUG
and
TRACE

Question 261

Instrumenting a program to trace it’s progress is known as?

Answer 261

Tracing

Question 262

Name the methods to support logging

Answer 262

1. Writing to a text file
2. Using DEBUG and TRACE with a listener to write to a
   text file
3. Writing to an event log

Question 263

The recording of key events is known as?

Answer 263

logging

Question 264

What methods are used to support profiling?

Answer 264

1. Using a profiler
2. Instrumenting code by hand
3. Performance counters

Question 265

Gathering information about a program to study characteristics such as speed and memory usage is referred to as?

Answer 265

Profiling

Question 266

A test on data ot see if the data makes sense is referred to as a ?

Answer 266

sanity check

Question 267

What is tracing?

Answer 267

The process of instrumenting a program so that you can track what it is doing

Question 268

What is a regular expression?

Answer 268

An expression in regular expression language that defines a pattern to match.

Question 269

What is profiling?

Answer 269

The process of instrumenting a program to study it’s speed, memory, disk usage, or other performance characteristics.

Question 270

An automated tool that gathers performance data for a program by it’s code or by sampling is referred to as?

Answer 270

a profiler.

Question 271

What is a performance counter?

Answer 271

A system-wide counter used to track some type of activity on the computer.

Question 272

A regular expression used for matching parts of a string is called?

Answer 272

a pattern

Question 273

What is logging?

Answer 273

The process of instrumenting a program so it records key events?

Question 274

Adding features to a program to study the program itself is called?

Answer 274

instrumenting

Question 275

Options set in a regular expression using the syntax

(?imasx) are referred to as ?

Answer 275

inline options

Question 276

A sequence of characters that have special meaning in a regular expression is referred to as a ?

Answer 276

escape sequence

Question 277

Define data validation

Answer 277

Program code that verifies that a data value makes sense

Question 278

A predefined symbol created by Visual Studio that you can use with #if, #elif, #else and #endif directives to determine what code is in the program?

Answer 278

Conditional Compilation Constant

Question 279

A regular expression construction that represents a set of characters to match is?

Answer 279

character class

Question 280

A piece of code that makes a particular claim about data and throws an exception if that claim is false is called?

Answer 280

An assertion

Question 281

What method is used to create assertions?

Answer 281

System.Diagnostics.Debug.Assert

Question 282

Given the following:
MyClass myClass = new MyClass();
MethodInfo myMethod =
typeof(MyClass).GetMethod(“Multiply”);

using reflection, execute the method and pass in two parameters.

Answer 282

myMethod.Invoke(myClass,

new object[]{4,5});

Question 283

Which method of the MethodInfo class can be used to execute the method using reflection?

Answer 283

Invoke

Question 284

Assume myClass is an instance of a class.

Create a statement that returns a private instance field called “myPrivateInstance” using reflection.

Answer 284

MyClass.GetType().GetField(“myPrivateField”,
BindingFlags.NonPublic |
BindingFlags.Instance);

Question 285

Which property of the Type class can you use to determine the number of dimensions in an array?

Answer 285

GetArrayRank

Question 286

Which class in the System.Reflection namespace is used to represent a field defined in a class?

Answer 286

FieldInfo

Question 287

Using reflection, how an you determine if a class is public or private?

Answer 287

Create an instance of the Type class using typeof() and then examine the IsPublic propery of the Type variable

Question 288

Which class would you create if you wanted to determine all properties contained in a class using reflection?

Answer 288

Type

Question 289

Create an instance of a DataTable using reflection

Answer 289

myAssembly.CreateInstance(“System.Data.DataTable”);

Question 290

Which method should you call if you want .NET Framework to look in the load-from context?

Answer 290

LoadFrom

Question 291

Which method should you call if you want the .NET Framework to look in the load-context to load an Assembly?

Answer 291

Load

Question 292

Define the syntax to load an assembly

Answer 292

1. Assembly.Load(“System.Data”,
   Version=4.0.0.0,
   Culture = neutral,
   PublicKeyToken=b77a5c561934e089);
2. Assembly.LoadFrom(@”c:\myProject\Project1.dll”);
3. Assembly.LoadFile(@”c:\myProject\Project1.dll”);
4. Assembly.ReflectionOnlyLoad(“System.Data”,
   Version=4.0.0.0,
   Culture = Neutral,
   PublicKeyToken=b77a5c561934e089);

Question 293

Which method of the Assembly class returns an instance of the current assembly?

Answer 293

GetExecutingAssembly

Question 294

Which property of the Assembly class returns the name of the assembly?

Answer 294

FullName

Question 295

Which method of the Assembly class allows you to get all the public types defined in the assembly?

Answer 295

GetExportedTypes

Question 296

Which class in the System.Reflection namespace would you use if you want to determine all the classes contained in the .dll file?

Answer 296

Assembly

Question 297

You are asked to create a custom attribute that has a single property, called version, that allows the caller to determine the version of the method.

Which code creates the attribute?

Answer 297

class MyCustomAttribute:System.Attribute
{
  public string Version{get; set;}
}

Question 298

You are a developer for a finance department and are building a method that uses reflection to get a reference to the type of object passed as a parameter.

Which syntax is used to determine object type?

Answer 298

Type myType = myParameter.GetType();

Question 299

You are consulting for a company called Contoso and are taking over an application that was built by a third party.

How can you figure out which .dll files are being referenced?

Answer 299

1. Create an instance of the assembly class
2. Load the assembly
3. Call the GetReferencedAssemblies method

Question 300

What code creates a lambda expression returning the squares of an integer?

Answer 300

x => x * x;

Question 301

You are given an assignment to create a code generator to automate the task of creating repetitive code.

Which namespace contains the types needed to generate code?

Answer 301

System.CodeDom

Question 302

The process that permits parameter types that are less derived than the delegate type?

Answer 302

Contravariance

Question 303

The process that enables you to have a method with a more derived return type than the delegate return type is ?

Answer 303

Covariance

Question 304

The => symbol in a lambda expression is referred to as?

Answer 304

goes to

or

such that

Question 305

What is a delegate?

Answer 305

A type that references a method

Question 306

Shorthand syntax for anonymous functions are referred to as?

Answer 306

lambda expressions

Question 307

What class generates the class file in either C#, VB or JScript?

Answer 307

System.CodeDom.CodeDomProvider

Question 308

In the codeDom, what class is the top level class?

Answer 308

System.CodeDom.CodeCompileUnit

Question 309

What is the CodeDom?

Answer 309

Code Document Object Model

As set of classes that enables you to create code generators

Question 310

Custom attributes inherit from what class?

Answer 310

System.Attribute

Question 311

How is an attribute declared?

Answer 311

By decorating with square brackets []

Question 312

What enables you to create metadata for a class, property or method?

Answer 312

Attributes

Question 313

What method returns a PropertyInfo object and enables you to set or get a property’s value?

Answer 313

Type.GetProperty

Question 314

What does System.Type represent?

Answer 314

A class, interface, array, value type, enumeration, parameter, generic type definition and open or closed generic types.

Question 315

What method creates an instance of a type?

Answer 315

Assembly.CreateInstance

Question 316

What method loads the assembly but does not enable execution?

Answer 316

Assembly.ReflectionOnlyLoad

Question 317

What method loads an assembly into memory and enables you to execute code?

Answer 317

Assembly.Load

Question 318

What class is used to examine the types within an .exe or .dll file?

Answer 318

System.Reflection.Assembly

Question 319

Name the two ways to get a reference to the Type object

Answer 319

typeof()

and

.GetType()

Question 320

What is a type?

Answer 320

A class, interface, array, value type, enumeration, parameter, generic type definition, open or closed generic type.

Question 321

The class, porperty or method that contains metadata defined by an attribute is called the…?

Answer 321

Target

Question 322

A lamdba expression containing more than one statement in the body of the expression is referred to as a …?

Answer 322

statement lambda

Question 323

What is reflection?

Answer 323

Provides lasses that can be used to read metadata or dynamically invoke behavior from a type?

Question 324

Describe probing

Answer 324

The process of looking in the GAC, the host assembly store, the folder of the executing assembly, or the private bin folder of the executing assembly to find an assembly

Question 325

A file, typically a .dll or .exe that composes an assembly is referred to as a ..?

Answer 325

module

Question 326

When loading an assembly using reflection, what context contains the assemblies located inthe path passed into LoadFrom method.

Answer 326

load-from context

Question 327

When loading an assembly during reflection, what context contains the assemblies found by probing

Answer 327

load context

Question 328

Define a lambda expression

Answer 328

Shorthand syntax for an anonymous method that can be associated with a delegate or expression tree.

Question 329

A variable in a class or structure is referred to as a ..?

Answer 329

field

Question 330

Code in a tree-like structure where each node is an expression is referred to as a…?

Answer 330

Expression tree

Question 331

What is an expression lambda?

Answer 331

An expression that contains one statement for the body.

Question 332

What type is a reference to a method?

Answer 332

delegate

Question 333

Define covariance

Answer 333

Enables you to have a method with a more derived return type than the delegates return type

Question 334

Define contravariance

Answer 334

Permits parameter types that are less derived than the delegates parameter types.

Question 335

When loading an assembly using reflection, where does reflection search for the assembly?

Answer 335

in the context

Question 336

Define the CodeDOM

Answer 336

Code Document Object Model

Enables the developer to generate code in multiple languages at run time based on single code set.

Question 337

What enables you to associate metadata with assemblies, types, methods, properties…?

Answer 337

attributes

Question 338

A compiled piee of code in a .dll or .exe is referred to as a ?

Answer 338

assembly

Question 339

What method enables you to associate a block of code with a delegate without a method signature?

Answer 339

anonymous methods

Question 340

If during Garbage Collection a program has no path of references that access the object, the object is ?

Answer 340

unreachable

Question 341

Resources that are not under the control of the CLR are known as?

Answer 341

unmanaged resources

Question 342

A base or parent class is also known as?

Answer 342

the superclass

Question 343

The process of deriving a subclass from a base class through inheritance is referred to as ?

Answer 343

subclassing

Question 344

What is a subclass?

Answer 344

A derived class

Question 345

Classes that have the same parent class are referred to?

Answer 345

sibling class

Question 346

A copy of an object where reference fields refer to the same objects as the original is a ..?

Answer 346

shallow clone

Question 347

If the program has a path of references that allow access to the object than it is?

Answer 347

reachable

Question 348

A base, or superclass is known as the?

Answer 348

parent class

Question 349

Because you cannot direct when the GC will call an objects Finalize method, the process is referred to as ?

Answer 349

Nondeterministic finalization

Question 350

Allowing a child class to have more than one parent class?

Answer 350

multiple inheritance (not allowed in C#)

Question 351

Resources that are under the control of the CLR are?

Answer 351

managed resoources

Question 352

Using an interface to require a class to provide certain features much as inheritance does is referred to as ?

Answer 352

Interface inheritance

Question 353

What does it mean to inherit?

Answer 353

A derived class inherits the properties, methods, events and other code from the base class.

Question 354

The process that executes periodically to reclaim memory that is no longer accessible to the program

Answer 354

Garbage Collection (GC)

Question 355

What is Garbage Collection?

Answer 355

The process of running the Garbage Collector to reclaim memory no longer available to the program

Question 356

A queue through with object with finalizers must pass before being destroyed is called the ?

Answer 356

finalization queue

Question 357

What is finalization?

Answer 357

The process of the garbage collection calling the objects Finalize method.

Question 358

What is a destructor?

Answer 358

A method with no return type and the class name preceded by the ~ symbol

Question 359

A class’s children, as well as their children are referred to as?

Answer 359

descendant class

Question 360

The creation of one class based on another through inheritance is referred to ?

Answer 360

deriving a class

Question 361

A copy of an object where reference fields refer to new instances of objects?

Answer 361

deep clone

Question 362

A virtual machine that manages C# ( and other .NET) programs is the ?

Answer 362

Common Language Runtime (CLR)

Question 363

A class derived from a parent class is referred to as the ?

Answer 363

child class

Question 364

A class from which another class is derived via inheritance is referred to as the ?

Answer 364

base class

Question 365

A class parent is referred to as an ?

Answer 365

ancestor class

Question 366

What is the purpose of tying the using statement to the Dispose method?

Answer 366

The program automatically calls the Dispose method and limits the object scope to the block.

Question 367

Why does the Dispose method call GC.SuppressFinalize?

Answer 367

Prevents the garbage collector from running objects destructor and keeps the object out of the finalization queue.

Question 368

What resources are freed by a destructor?

Answer 368

unmanaged resources

Question 369

What resources should be freed in a Dispose method?

Answer 369

manage and unmanaged resources

Question 370

Yes or No

Can a dispose method be executed more than once?

Answer 370

Yes

Question 371

Yes or No

For classes with only unmanaged resources, should IDisposable be implemented?

Answer 371

Yes and it needs to implement a destructor

Question 372

Yes or No

For classes with managed resources, should IDisposable be implemented?

Answer 372

Yes, but a destructor is not required

Question 373

Yes or No

Do classes with no managed or unmanaged resource require an implementation of IDisposable?

Answer 373

No

A destructor is not required

Question 374

What methods are destructors converted to by the compiler?

Answer 374

Finalize

Question 375

Yes or No

Can access modifiers or parameters be defined on a destructor?

Answer 375

No

Question 376

True or False

Destructors can be inherited or overloaded?

Answer 376

False

Question 377

How many destructors can be assigned to a class?

Answer 377

No more than one

Question 378

True or False

Destructors may be defined in structs and classes

Answer 378

False

Destructors are only defined in classes

Question 379

How are objects added to an IEnumerator result

Answer 379

yield return

Question 380

Which interface returns an object used for moving through lists of objects?

Answer 380

IEnumerable

Question 381

What method of ICloneable returns a copy of the object?

Answer 381

Clone

Question 382

What interface provides an equal method to determine if two objects are equal to one another?

Answer 382

IEquatable

Question 383

What interface provides a Compare method to compare two objects to determine their ordering?

Answer 383

IComparer

Question 384

What method from IComparable is provided to determine the order of objects?

Answer 384

CompareTo

Question 385

When code can use either a class instance or interface instance to access the interface, then the interface was implemented how?

Answer 385

implict

Question 386

Define interface inheritance

Answer 386

The act of implementing an interface

Question 387

If a class implements an inteface explicitly, how is the explicit reference acessed?

Answer 387

It must use an interface instance

Question 388

How many classes and interfaces can a class inherit?

Answer 388

one class 
any number of interfaces

Question 389

Buy convention, interface names begin with what letter?

Answer 389

I (IEnumerable, etc)

Question 390

True or False

If a parent class has constructors, the child class constructor must invoke them directly or indirectly

Answer 390

True

Question 391

True or False

At most, a constructor can invoke one base class or one same class constructor.

Answer 391

True

Question 392

Use the this keyword to create a snippet to make a constructor invoke another constructor in the same class

Answer 392

public class ClassName
{
  public object PropertyName{get; set;}
  public object PropertyName2{get; set;}
  public ClassName(object x)
  {
    propertyName = x;
  }
public ClassName(object x, object y)
   : this( PropertyName(x))
{
  propertyName2 = y;
}

Question 393

Use the base keyword to make a constructor to invoke the parent constructor

Answer 393

public class Child
  :Parent
{
  public Child(obj x, obj y) : base(x, y)
  {
    // Do something
  }
}

Question 394

Does C# support multiple inheritance?

Answer 394

No

Question 395

If a class has unmanaged resources and no managed resources should IDisposable provide a destructor?

Answer 395

Yes

Implement IDisposable and provide a destructor

Question 396

If a class has managed resources and no unmanaged resources should IDisposable provide a destructor?

Answer 396

No

Implement IDisposabel but provide no destructor

Question 397

If a class implements IDisposable, what three steps should be completed by the Dispose method?

Answer 397

1. Free the managed resources
2. Free unmanaged resources
3. Call GC.SuppressFinalize

Question 398

True or False

Destructors are inherited?

Answer 398

False

Question 399

True or False

Before destroying an object, the Garbage Collector (GC) calls it’s Dispose method?

Answer 399

False

The GC calls the Finalize method

Question 400

The IEnumerable and IEnumerator interfaces provide what methods to move through a list of objects?

Answer 400

MoveNext

and

Reset

Question 401

True or False

A class can inherit from at most one class and implement any number of interfaces

Answer 401

True

Question 402

Suppose you want to sort the recipe class by any of the properties; main ingredients, total time or cost per person.

Which interface would probably be most useful?

Answer 402

IComparer

Question 403

Suppose you want to make a recipe class to store cooking recipes and you want to sort the recipes by the main ingredient property.

Which interface would be most useful?

Answer 403

IComparable

Question 404

Is code reuse a goal of interface design?

Answer 404

No

The goals are

1. Simulating multiple inheritance
2. Treating unrelated objects in uniform way
3. Polymorphism

Question 405

Suppose the Houseboa class implements the IHouse interface implicitly and the IBoat interface explicitly.

Can the code use Houseboat object to access the IBoat members?

Answer 405

No

Question 406

Suppose you have defined the House and Boat classes and you want to make a HouseBoat class that inherits from House and Boat.

Can you inherit from both House and Boat?

Answer 406

No

C# classes support single inheritance

Question 407

If the base statement is declared first, can the constructor use a this statement and a base statement?

Answer 407

No

Question 408

Does the use of the base keyword allow a constructor to invoke a different constructor in the same class?

Answer 408

No

Question 409

You are working on a global application with lots of users. The operartion staff requests information on how many user logons per second are occurring.

What should you do?

Answer 409

Implement a performance counter using the RateOfCountsPerSecond64 type

Question 410

Users are reporting errors in your application, and you want to configure your application to output more trace data.

Which configuration setting should you use?

Answer 410

Switch

The switch value determines which trace events should be handled.

Question 411

You are using the TraceSource class to trace data when an order cannot be submitted to the database and you are going to perform a retry.

Which TraceEventType should you use?

Answer 411

Error

Alerts that something is wrong that needs to be recovered.

Question 412

When experience performance problems, what can you do to isolate and resolve root cause?

Answer 412

Profile the application

Question 413

What classes are used to log and trace messages?

Answer 413

DEBUG

and

TRACE

Question 414

When should logging and tracing be implemented?

Answer 414

from the beginning of the project

Question 415

You are using custom code generation to insert security checks into your classes.

When an exception occurs, you’re having trouble finding the correct line in your source code.

What should you do?

Answer 415

Use the #line directive with the correct line numbers in your generated code to restoring the original line numbers

Question 416

You are debugging an application for a web shop and are inspecting a lot of Order classes.

What can you do to make your debugging easier?

Answer 416

Use the DebuggerDisplayAttribute on the Order class

Question 417

You are ready to deploy your code to a production server.

Which configuration do you deploy?

Answer 417

Release configuration

Question 418

What build outputs code that can be deployed to production?

Answer 418

Release build

Question 419

What tools are provided to give extra instructions to the compiler.

Answer 419

compile directives

Question 420

What type of build outputs a nonoptimized version of the code that contains extra instruction to help debugging?

Answer 420

Debug build

Question 421

The compiler can be configured in Visual Studio through use of what tool?

Answer 421

Build configurations

Question 422

You want to deploy an assembly to a shared location on the intranet.

Which steps should you take?

Answer 422

Strongly name the assembly

Use the codebase configuration element in the applications that use the assembly

Question 423

You are building an assembly that will be used by a couple server applications.

You want to move the update process of this assembly as smooth as possible.

Which steps should you take?

Answer 423

1. Deploy the assembly to the GAC

2. Strongly name the assembly

Question 424

You are building a stong-named assembly and you want to reference a regular assembly to resuse some code you built.

What steps need to be taken?

Answer 424

You need to sign the other assembly before using it.

Question 425

How are applications bound to the assemblies they were developed with?

Answer 425

by using versioning

Question 426

What is a WinMD assembly?

Answer 426

A special type of assembly used by WinRT to map non-native languages the native WinRT components.

Question 427

Signed assemblies may be placed where?

Answer 427

inside the Global Assembly Cache (GAC)

Question 428

To prevent tampering what may be done to an assembly?

Answer 428

Strongly signed

Question 429

A compiled unit of code that contains metadata is referred to as an ?

Answer 429

assembly

Question 430

You need to send sensitive data to another party and you want to make sure that no other party tampers with the data.

Which method do you use?

Answer 430

X509Certificate2.SignHash

Question 431

You need to encrypt a large amount of data.

Which algorithm should yoour use?

Answer 431

AESManaged

Question 432

Boba and Alice are using an asymmetric algorithm to exchange data. Which key should they send to the other party to make this possible?

Answer 432

Bob sends Alice his public key

Alice sends Bob her public key

Question 433

What is the method used to verify the authenticity of an author?

Answer 433

Digital Certificates

Question 434

What process is used to retrict the resources and operations an application can access and execute.

Answer 434

CAS

Question 435

What is the purpose of System.Security.SecureString?

Answer 435

Maintains sensitive string data in memory

Question 436

What is hashing?

Answer 436

The process of converting a large amount of data to a smaller hash code

Question 437

What algorithm uses a public and private key that are mathematically linked?

Answer 437

Asymmetric algorithm

Question 438

What algorithm uses the same key to encrypt and decrypt data?

Answer 438

Symmetric algorithm

Question 439

You need to validate an XML file.

What do you use?

Answer 439

XML Schema Definition (XSD)

Question 440

You are working on a globalized web application. You need to parse a text field where the user enters an amount of money.

What method do you use?

Answer 440

You need to specify the number styles. Currency and culture that the user is using.

decimal.TryParse(value,
NumberStyles.Currency,
UICulture);

Question 441

A user needs to enter a DateTime in a text field. You need to parse value in code.

Which method do you use?

Answer 441

DateTime.Parse

Question 442

When receiving JSON and XML files, it is important to validate them using what built-in types.

Answer 442

JavascriptSerializer
and
XMLSchemas

Question 443

What can be used to match input against a specified pattern or replace specified characters with other values?

Answer 443

regular expressions

Question 444

What functions are used to convert between types?

Answer 444

1. Parse
2. TryParse
3. Convert

Question 445

Where is data integrity managed?

Answer 445

By your application and your data store

Question 446

Why is validating application input important?

Answer 446

To protect your application from mistakes and/or attacks

Question 447

What steps are required to make sure data is not modified while transferred?

Answer 447

1. Calculate the cryptographic hash
2. Send the hash with the data
   for validation by the receiving party.

Question 448

Name two commonly used hashing algorithms?

Answer 448

SHA256

SHA512

Question 449

Mapping binary data of a variable length to a fixed size binary data is called?

Answer 449

hashing

Question 450

How are asymmetric private keys secured?

Answer 450

By using certificates or by using Crypto Service Providers containers

Question 451

How are symmetric keys exchanged?

Answer 451

Using asymmetric algorithms

Question 452

Name the four parts of an assembly version

Answer 452

Major
Minor
Build
Revision

Question 453

Name the five parts of a strong name assembly

Answer 453

Friendly name
Version
Culture
Public Key Token
Processor Architecture

Question 454

What is an assembly called that has been digitally signed?

Answer 454

strong named assembly

Question 455

Can more than one version of an assembly be deployed to the GAC?

Answer 455

Yes

Several versions of the same assembly can be deployed on the GAC at the same time.

Question 456

What type of assemblies can be deployed to the GAC?

Answer 456

only strong named assemblies

Question 457

What is the GAC?

Answer 457

Global Access Cache

A repository to share .NET assemblies

Question 458

A cryptographic protocol used for secure communication ove the Internet, the successor of SSL is called?

Answer 458

Transport Layer Secuirty (TLS)

Question 459

Which method would you call when you use a barrier to mark that a participant reached that point?

Answer 459

SignalAndWait

Question 460

How can you schedule work to be done by a thread from a threadpool?

Answer 460

1. Call the ThreadPool.QueueUserWorkItem

2. Create a new thread and set property

Question 461

You are a developer at ompany xyz. You have been asked to improve the responsiveness of your WPF application.

Which solution best fits the requirement?

Answer 461

BackgroundWorker class

Question 462

Define contravariance

Answer 462

Allow a method to take parameters that are from a superclass of the type expected by the delegate

Question 463

Define covariance

Answer 463

Allows a method to return a value from a subclass of the result expected by a delegate

Question 464

What methods can you use to catch integer overflow exceptions?

Answer 464

1. Use a checked block and a try-catch-finally block

2. Check the advanced build setting dialogue flow box and use a try-catch-finally block

Question 465

True or False

Can a try-catch-finally block next inside a try-catch-finally block?

Answer 465

Yes

Question 466

True or False
A derived class can raise a base class event by using code similar to the following:
if( base.EventName != null)
bse.EventName(this, args)

Answer 466

False

A derived class cannot raise an event defined in an ancestor class.

Question 467

If an object subscribes to an event once and then unsubscribes twice, does the event handler throw an exception when the event is raised.?

Answer 467

No

Question 468

Suppose the card class provides a stopped event that takes as parameters sender and stopped ars objects. Suppose also that the code has already created an appropriate stopped args named args.

How do you raise the event?

Answer 468

if( Stopped != null)

Stopped(this, args);

Question 469

How do you evaluate if the variable result holds the value

float.PositiveInfinity

Answer 469

1. result == float.PostiveInfinity
2. float.IsInfinity(result)
3. float.IsPositiveInfinity(result)

Question 470

Which of the following should you not do when building a custom exception class?

Answer 470

Make it implement IDisposable

Question 471

How are events customized?

Answer 471

By adding a custom event accessor and by directly using the underlying delegate type

Question 472

How are events raised?

Answer 472

Events are raised by the declaring class

Users of events can only remove or add methods to the invocation list.

Question 473

Define events

Answer 473

A layer of ‘syntatic sugar’ on top of delegates to easily implement the publish/subscribe pattern.

Question 474

Define lambda expression

Answer 474

Anonymous methods that use the => operator and form a compact way to create inline functions.

Question 475

Define delegates

Answer 475

A type that defines a method signature and cna contain a reference to a method.

Delegates can be instantiated passed around and invoked

Question 476

Define Task

Answer 476

A unti fo work

Question 477

Define scheduler

Answer 477

A component of the OS that slices time between threads

Question 478

Define race condition

Answer 478

Occurs when two or more threads access the same data for write operations

Question 479

Define mutual exclusion

Answer 479

The problem of ensuring two threads can’t be in the same critical section at the same time.

Question 480

Define multithreading

Answer 480

An operating system or hardware platform that can have several threads operating at the same time.

Question 481

Define fork-join pattern

Answer 481

Process of spawning another thread from the current thread to do work while current thread continues.

The current thread waits for spawned thread to finish (using Join)

Question 482

Define EAP

Answer 482

Event-Based Asynchronous Pattern

Pattern requires a method to be suffixed with async and provide delegates to signal completion or failure.

Not recommended for new development

Question 483

Define

What four conditions lead to a deadlock

Answer 483

1. Mutual exclusion
2. Hold and Wait
3. No preemption
4. Circular wait

Question 484

Define

Deadlock

Answer 484

Two or more threads that attempt to acquire a lock on a resource

Question 485

Define

Atomic Operation

Answer 485

An operation that runs once without interruption by the scheduler

Question 486

Define

APM

Answer 486

Asynchronous Pattern Model
Pattern split into two parts
  Begin : Prepares the call and expects immediate    
               return
  End : Called to return result

Used with existing development

Question 487

Define

Asynchrony

Answer 487

Operations run in a non-blocking fashion

Question 488

How do you execute a method as a task?

Answer 488

1. Create a new task, then call the Start method
2. Create and run task (Task.Run())
3. Create and run task via Task.Factory.StartNew()

Question 489

Which method can be used to cancel an ongoing operation that uses a cancellation token?

Answer 489

Call the cancel method on the CancellationTokenSource used to create the CancellationToken

Question 490

You are processing some data over the network. You use a HasNext and Read method to retrieve the data. You need to run some code on each item.

What do you use?

Answer 490

do-while loop

Question 491

You have a lot of checks in your applicaiton for null values. If a value is not null, you want to call a method on it.

Which technique would you use?

Answer 491

null-coalescing operator

Question 492

You need to iterate over a collection in which you know the number of items. You need to remove certain items from the collection.

Which statement do you use?

Answer 492

for

Cannot remove certain items from the collection using foreach

Question 493

You want your type to be able to be converted from string. Which interface should you implement?

Answer 493

IFormattable

Question 494

You want to deploy only the date portion of a DateTime according to the French culture.

What method should you use?

Answer 494

dt.ToString(“d”, new CultureInfo(“fr-FR”));

d = specifies date
fr-FR specifies French language

Question 495

You are parsing a lage piece of text to replace values based on some complex algorithm.

Which class should you use?

Answer 495

StringBuilder

Question 496

Name six methods for dealing with strings

Answer 496

IndexOf
LastIndexOf
StartsWith
EndsWith
SubString

Question 497

What is the purpose of StringBuilder?

Answer 497

To enhance the performance of string manipulations

Question 498

Define strings

Answer 498

An immutable reference type

Question 499

Your application is using a lot of memory.

Which solution should you address with?

Answer 499

Use a caching element to decide which objects can be freed.

You then decie the criteria for freeing memory.

Question 500

Yes or No

An object that is implementing IDisposable is passed to your class as an argument. Should you wrap the element in a using statement?

Answer 500

No

The calling method should dispose of the object with a using statement

Question 501

You are about to execute a piece of code that is performance sensitive. You are afraid that a garbage collection will occur during the execution of this code.

Which method should you call before executing your code?

Answer 501

GC.Collect()

Collect will execute a garbage collection, freeing as much memory as possible at that time. It makes further garbage collection less likely to happen.

Question 502

When is a WeakReference used?

Answer 502

To maintain a reference to items that can be garbage collected when necessary.

Question 503

How can yo make sure resources are freed when implementing IDisposable?

Answer 503

By implementing a using statement

Question 504

What is the purpose of IDisposable?

Answer 504

To free unmanaged resources in a deterministic way.

Question 505

What piece of code is executed by the garbage collector when disposing of an object?

Answer 505

Finalizer

Question 506

What comprises memory in a C# program?

Answer 506

Stack (local variables)

Heap (global variables, method/functions)

Question 507

You want to read the value of a private field on a class. Which Binding Flags do you use?

Answer 507

Instance because the filed is non-static

NonPuiblic as the filed is declared private

ex. BindingFlags.Instance | BindingFlags.NonPublic

Question 508

Memory allocation is managed on the heap by what process?

Answer 508

Garbage Collection (GC)

Question 509

You want to create a delegate that can filter a list of strings on a specific value.

What type should you use?

Answer 509

Func, IEnumerable);

string = filter
IEnumerable = input list
IEnumerable = returned filtered list

Question 510

You need to create an attribute that can be applied multiple times on a method or parameter.

Which syntax should you use?

Answer 510

[AttributeUsage( AttributeTargets.Method
| AttributeTargets.Parameter,
AllowMultiple = true)]

Question 511

Define expression trees

Answer 511

Expression trees describe a piece of code.

Expression trees can be translated to something else (SQL) or compiled and executed.

Question 512

Describe the purpose of the CodeDOM

Answer 512

Used to create a compilation unit at runtime

The unit can be compiled or converted to a source file.

Question 513

Define Reflection

Answer 513

The process of inspecting the metadata of a C# application

Question 514

Define Attributes

Answer 514

A type of metadata that can be applied in code and queued at runtime

Question 515

What is stored in a C# assembly?

Answer 515

Code and metadata

Question 516

You want to inherit from an existing class and add some behavior to a method.

Name the steps.

Answer 516

Use the virtual keyword on the base method

Use the override keyword on the derived method

Question 517

You want to create a type that can be easily sored.

Which interface should you implement?

Answer 517

IComparable

IComparable enables objects to be compared to each other.

Question 518

Define IComparable

Answer 518

Interface used to sort elements

Question 519

You want to create a hierarchy of types because you have some implementation code you want to store between all types. You also have some method signatures you want to store.

What should you use?

Answer 519

An abstract class

The abstract class enables you to store both implemented methods and method signatures that a derived class needs to implement.

Question 520

Define IUnknown

Answer 520

Wrapper used to add com objects that are unable to be wrapped by the compiler

Question 521

Define IDisposable

Answer 521

Facilitates working with external unmanaged resources

Question 522

Define IEnumerable

Answer 522

Allows you to iterate over items in the collection

Question 523

Name four primary default interfaces provided by the .NET framework

Answer 523

IComparable
IEnumerable
IDisposable
IUnknown

Question 524

How can you prevent a class from being inherited?

Answer 524

Mark the class as sealed

Question 525

What is the significance of marking a class abstract?

Answer 525

The class cannot be instantiated and can function only as a base class.

Question 526

Name the three C# data structures

Answer 526

Structs
Enums
Classes

Question 527

Where are value types defined?

Answer 527

Within the .NET Framework

Question 528

How are value types based?

Answer 528

On the number of bits used to store the type

Question 529

How are value types passed to methods?

Answer 529

As a copy

Question 530

Value types are an alias for what object?

Answer 530

System

Question 531

How are value types stored?

Answer 531

Directly

Question 532

How are object values passed in generic methods?

Answer 532

They are passed by reference

Question 533

What does the designator indicate in a generic class?

Answer 533

Serve as a placeholder that will contain the object used

Question 534

What is an advantage of using Generics in .NET?

Answer 534

Generics enable you to create classes that accept the type at creation time.

Question 535

Name on advantage of using named parameters

Answer 535

You can pass the parameters in to the method in any order using parameter names

Question 536

Boxing refers to ?

Answer 536

Converting a value type to a reference type

Question 537

How do enforce encapsulation on the data members of your class?

Answer 537

Create private data members
and
Public properties

Question 538

When you create an abstract method, how do you use that method in the derived class?

Answer 538

You must override the method in your derived class

Question 539

What is the parameter in this method known as?

public void displayAbsoluteValue( int value  = 1)
{
  //Do Something
}

Answer 539

Optional

Question 540

What are two methods with the same name but with different parameters referred to as?

Answer 540

Overloaded methods

Question 541

In the following enumeration, what will be the underlying value of Wed?

enum Days{Mon-1, Tues, Wed, Thur, Fri, Sat, Sun}

Answer 541

3

Question 542

What is the correct way to access the firstname property of a struct named Student

Answer 542

var firstName = Student.firstname;

Question 543

True or False

Can structs contain methods?

Answer 543

True

Question 544

Which declaration can assign default value to an int type:

Answer 544

int myInt = new int();

Question 545

True or False

double and float types can store values with decimals?

Answer 545

True

Question 546

What is the maximum value you can store in an uint data type?

Answer 546

4,294, 967, 296

Question 547

Define main property abstract methods

Answer 547

Abstract methods do not define and implementation

Question 548

How are overloaded methods defined?

Answer 548

By signature name, types and parameters

Question 549

What purpose do methods serve in classes?

Answer 549

Provide the functionality of the class

Question 550

How many parameters may the default constructor specify?

Answer 550

None

Default constructors have no parameters

Question 551

How are constructors named?

Answer 551

With the same name as the class

Question 552

Do constructors specify a return type?

Answer 552

No

Question 553

What is the purpose of the constructor?

Answer 553

To initialize the class

Question 554

What is the purose of fields within a class?

Answer 554

To house data for the class

Question 555

To avoid unwanted modifications, how should fields be marked?

Answer 555

private

Question 556

Name the modifiers that can be used when declaring classes?

Answer 556

internal
private
public
protected
protected internal

Question 557

What is the purpose of class modifiers?

Answer 557

To determine access for classes and class members

Question 558

What is the purpose of member functions within a class?

Answer 558

To describe functionality

Question 559

What is the purpose of member variables within a class?

Answer 559

To describe characteristics or properties

Question 560

Reference types are commonly referred to as?

Answer 560

classes

Question 561

What is the underlying type of enums?

Answer 561

Integers beginning at 0, unless the declaration specified in declaration specifies otherwise

Question 562

How are enumerations formed?

Answer 562

As a list of named constants

Question 563

How are structs passed to methods?

Answer 563

By value

Question 564

Define structs

Answer 564

Lightweight data structures

Question 565

How can derived classes act on base classes marked as virtual?

Answer 565

Derived classes can override virtual methods to add or replace behavior.

Question 566

A class is limited to inheriting how many interfaces?

Answer 566

No limit, unlimited

Question 567

A class is limited to inheriting how many classes?

Answer 567

One, C# support single class inheritance

Question 568

Define interface

Answer 568

An interface specifies the public elements a type myst implement

Question 569

Define inheritance

Answer 569

The process in which a class is derived from another class or from an interface

Question 570

Define generic types

Answer 570

Type parameter used to make code more flexible

Question 571

Name the types in C#

Answer 571

Value Types

Reference Types

Question 572

Define casting

Answer 572

An explicit conversion that requires special syntax

Question 573

Name the conversion options for types

Answer 573

Implicit

Explicit

Question 574

Define boxing

Answer 574

Boxing occurs when a value type is treated as a reference type

Question 575

What keyword can be used to ease the static typing of C# and improve interoperability with other languages

Answer 575

dynamic

Question 576

You have a class that implements two interfaces with the same name. Interface IA should be the default implementation. Interface IB should be used only in special situations.

How do your implement these interfaces?

Answer 576

Implement IA implicitly (makes IA default) and IB explicitly.

Question 577

You need to expose some data from a class. The data can be read by other types but can be changed only by derived types.

What should you use?

Answer 577

A public property with a protected set modifier.

Question 578

What access modifiers should you use to make sure that a method in a class can only be accessed inside the same assembly by derived types?

Answer 578

The class should be marked internal (only accessed inside project)

The members marked as protected (accessed by derived types)

Question 579

Name two uses of explicit interface implementation

Answer 579

1. To hide information

2. Implement interfaces with duplicate signatures

Question 580

Name the five access modifiers in C# development

Answer 580

private
public
internal
protected
protected internal

Question 581

How is accessability to types and type elements restricted?

Answer 581

Through use of access modifiers

Question 582

Define getters and setters

Answer 582

Property accessors that can run additional code

Question 583

How is data encapsulated in object-oriented design?

Answer 583

Through use of properties

Question 584

Why is encapsulation important in object-oriented design?

Answer 584

Hides internal details and improves usability of type

Question 585

You pass a struct variable into a method as and argument. The method changes the variable; however, when the method returns the method has not changed.

What happened?

Answer 585

Passing a value type makes a copy of the data.

The original value has not changed.

Question 586

You are creating a generic class that should work only with reference types.

Which type constraint should you add?

Answer 586

where T:struct

Question 587

You are creating a new collection type and you want to make sure the elements in it can be easily accessed.

What should you add to the type?

Answer 587

Indexer Property

Question 588

Define overriding

Answer 588

Enables you to redefine functionality from a base class in a derived class.

Question 589

How are C# types created?

Answer 589

Using ;
Constructors
Methods
Properties
Fields
Indexers

Question 590

Which method will you use to Signal and EventWaitHandle?

Answer 590

set

Question 591

In a multithreaded application how would you increment a variable called counter in a lock free manner?

Answer 591

Interlocked.Increment(ref counter);

Interlocked.Add(ref counter, 1);

Question 592

What code is equivalent with

lock(syncObject)
{
  // Do something
}

Answer 592

Monitor.Enter(syncObject);

try
{
}
finally
{
  Monitor.Exit(syncObject)
}

Question 593

Name methods that can be used to start or continue tasks

Answer 593

ContinueWith
WhenAll
WhenAny

Question 594

Name two methods to create and start a task

Answer 594

1. Task.Run()

2. Task.Factory.StartNew()

Question 595

An asynchronous unit of work is known as a ?

Answer 595

Task

Question 596

What instrument is used to reduce resource consumption when using threads?

Answer 596

Threadpools

Question 597

Which class abstracts task creation and makes it easier to deal with loops and parallel invokation of methods?

Answer 597

Parallel

Question 598

What class is used to run code in parallel?

Answer 598

The Parallel class

Question 599

What extension is used to run queries in parallel?

Answer 599

PLINQ

Question 600

You are creating a complex query that does not require any particular order and you want to run in parallel.

Which method should you use?

Answer 600

AsParallel()

Question 601

You have a lot of items that need to be processed.

For each item you need to perform a complex calculation.

Which technique should you use?

Answer 601

Parallel.For

Best for executing large number of items and processing concurrently.

Question 602

What class is used to create threads explicitly?

Answer 602

Thread class

Question 603

What class is used to allow runtime to handle threads?

Answer 603

Threadpools

Question 604

What is the recommended method to handle multithreaded code?

Answer 604

The Task object

Question 605

You are working on an ASP.NET application that retrieves some data from another web server and then writes the response to the database.

Should you use async and await?

Answer 605

Yes

This will free server resources to serve other requests waiting for I/O to complete

Question 606

What operators are sued to write asynchronous code more easily?

Answer 606

async and await

Question 607

What is the advantage of a thread?

Answer 607

Improves responsiveness and enables multiple CPU processing.

Question 608

How do u describe a thread?

Answer 608

A virtualized CPU

Question 609

What collection is used to work with data in a multithreaded environment?

Answer 609

Concurrent

Question 610

Define anonymous method

Answer 610

A method without a name.

You create a delegate that refers to code the method should contain

Question 611

How are delegates defined?

Answer 611

delegate(params)
{
  // Do Something
}

Ex. Func Square = delegate(float x)
{
return x * x;
};

Question 612

What is the general form of a lambda expression?

Answer 612

() => statement

Question 613

What is the general form of an asynchronous lambda?

Answer 613

async (params) => {
                                   // Do Something
                                };

Question 614

What is the general form of a statement lambda?

Answer 614

() => {
          // Do Something;
           return value;
         };

Question 615

Define subscriber

Answer 615

The class that catches the event

Question 616

Define publisher

Answer 616

An object that raises the event

Question 617

What operators are used to subscribe/unsubscribe to an event?

Answer 617

\+= Subscribes
-= Unsubscribe

Question 618

Define syntax for declaring an event

Answer 618

AccessModifier event delegate eventName

Ex.
public delegate void customEventHandler();

public event customEventHandler eventName;

Question 619

Describe the arguments passed to events

Answer 619

First parameter is the object raising the event

Second parameter is an object derived from EventArgs

Question 620

Define eventArgs

Answer 620

Arguments relevant to the event

Question 621

Describe form for declaring event arguments

Answer 621

class customEventArgs:EventArgs
{
  // instance variables
  public customEventArgs(instance variables)
  {
     // Do someting
  }
}

Question 622

Define Microsoft’s generic EventHandler delegate

Answer 622

public event EventHandler customEventName

Question 623

Define event inheritance

Answer 623

Problem
Events can only be raised from within the class that declared it.

Solution
Provide the base class a protected method that raises the event, then a derived class can call the method

Question 624

Define structure of inherited event

Answer 624

protected virtual void onMethod(customEventArg)
{
  // Do something
}

Question 625

Define the statement that subscribes the myButton_Click event handler to catch the myButton controls click event.

Answer 625

myButton.Click += myButton_Click;

Question 626

Suppose the Employee class is derived from the Person class and the Person class defines an AddressChanged event.

Which of the following should you do to allow an Employee object to raise this event?

Answer 626

1. Create an OnAddress changed method in the Person class that raises the event.
2. Make the Employee class call OnAddressChanged as needed.
3. Make the code in the Person class that used to raise the event call the OnAddressChanged method instead.

Question 627

Suppose the MovedEventHandler is defined by the statement

delegate void MovedEventHandler();

How do you define the Moved event?

Answer 627

public event MovedEventHandler Moved;

or

public event Action Moved;

Question 628

Define the attributes of statement lambda’s

Answer 628

A statement lambda can include more than one statement

A statement lambda must use braces

If a statement lambda returns a value it must use a return statement

Question 629

In the variable declaration

Action processor

the variable processor represents?

Answer 629

Methods that take Order as object and return void

Question 630

If an employee class inherits from the Person class, covariance allows you to?

Answer 630

Store a method that returns employee in a delegate that returns a Person

Question 631

If the Employee class inherits from the Person class. Contravariance allows you to?

Answer 631

Store a method that takes Person as a parameter in a delegate that represents methods that take an Employee as parameter

Question 632

Describe delegate variables

Answer 632

1. A struct or class can contain fields that are delegate variables
2. You can make an array or list of delegate variables
3. You can use addition to combine delegate variables and subtraction to remove a method from a series

Question 633

How is a delegate defined?

Answer 633

accessModifier delegate returnType delegateName(params)

Question 634

Name the tools associated with multithreading

Answer 634

TPL (Task Parallel Library)
Parallel class
PLINQ
async and await

Question 635

What actions can be performed with exceptions?

Answer 635

throw
catch
finally

Question 636

Define events

Answer 636

Events help to create the

publish-subscribe architecture

Question 637

Define lambda expression

Answer 637

Shorthand syntax for creating inline anonymous methods

Question 638

Define delegates

Answer 638

Objects that point to a method and can be used to make methods

Question 639

Name the jump statements

Answer 639

break
continue
goto
return
throw

Question 640

Name the iteration statements

Answer 640

for
foreach
while
do-while

Question 641

Name the decision statements

Answer 641

if
switch
? (conditional operator)
?? (null coalescing operator)

Question 642

In a multithreaded environment, it is important to manage synchronization of shared data using which tool?

Answer 642

lock statment

Question 643

You are creating a custom exception called LogonFailedException.

Which constructors should you add at minimum?

Answer 643

LogonFailedException(); //default
LogonFailedException(string);
LogonFailedException(string, exception);

Question 644

What keyword is used to raise an exception?

Answer 644

By using the throw keyword

Question 645

How can you specify code to run whether or not an exception occurs?

Answer 645

with the finally block

Question 646

How are exceptions typically caught in the .NET framework?

Answer 646

using the try..catch block

Question 647

Suppose the variable Note is declared by the statement Action Note.

Correctly initialize Note to an expression lambda.

Answer 647

Note = () => MessageBox.Show(“Hi”);

Question 648

Suppose the variable result is declared by the statement
Func result;

Correctly initialize result to expression lambda.

Answer 648

result = (float x) => x * x;

or

result = (x) => x * x;

Question 649

Suppose F is declared by the statement
Func F

Correctly initialize F to an anonymous method

Answer 649

F = delegate(float x)
{
return x* x;
}

Question 650

In the variable declaration
Func processor;

The variable processor represents?

Answer 650

A method that takes no parameters and returns and Order object

Question 651

The process of converting a boxed value back to it’s original value is known as ?

Answer 651

unboxing

Question 652

How are values displayed at a very high level?

Answer 652

Through standard formatting strings

Question 653

Define narrowing conversion

Answer 653

A data type conversion where the destination type cannot hold all possible values of the source.

Requires an explicit conversion

Question 654

What is interoperability

Answer 654

Interoperability enables managed code to use classes provided by unmanaged code not under control of CLR

Question 655

Define the intern pool

Answer 655

A table maintained by the CLR that contains a reference to every unique string used by the program

Question 656

What type of conversion occurs when a program automatically converts a value from one datatype to another

Answer 656

implicit

Question 657

Define immutable

Answer 657

A data type is immutable if its value cannot be changed after creation

Question 658

What do you create to build formats that are not provided by standard formatting strings?

Answer 658

custom formatting strings

Question 659

Describe an explicit conversion

Answer 659

Using a cast or method to explicitly tell a program how to convert a value from one type to another

Question 660

What format item used by string.Format indicates how an argument should be formatted?

Answer 660

The composit format
{
index[length][:formatString]
}

Question 661

What is the CLR?

Answer 661

Common Language Runtime

Manages execution of C# and other .NET programs

Question 662

What is the process of converting a value type such as a bool or integer into an object or interface?

Answer 662

boxing

Question 663

Name the most common DateTime formats

Answer 663

d: short date
D: long data
f: full date, short time
F:full date, full -time
M/m : Month, day
t: short time
T: long time
Y/y: year, month
g: general, short time
G: general, full time

Question 664

Why are standard format strings the preferred method?

Answer 664

They are locale-aware

Question 665

Name two methods that convert values into strings

Answer 665

.ToString()

string.Format()

Question 666

What classes provide methods for writing and reading characters and lines with an underlying StringBuilder object?

Answer 666

StringWriter

and

StringBuilder

Question 667

Your code catches an IOExceptionwhen a file cannot be accessed. You want to give more information to the caller of your code.

What do you do?

Answer 667

Throw a new exception with extra information that has the IOException as InnerException

Question 668

You are checking the arguments of your method fro illegal null values. If you encounter a NULL value, which exception do you throw>

Answer 668

ArgumentNullException

Question 669

Define exceptions

Answer 669

Objects that contain data about the exceptions

Question 670

How are errors reported in the .NET framework

Answer 670

via exceptions

Question 671

You have a private method in your class and you want to make invocation of the method possible by certain callers.

What do you do?

Answer 671

Use a method that returns a delegate to authorized callers

Question 672

You have declared an event on your class, and you want outside users of your class to raise this event.

What do you do?

Answer 672

Add a public method to your class that raises the event

Question 673

You are using a multicast delegate with multiple subscribers. You want to make sure that all subscribers are notified, even if an exception is thrown.

What do you do?

Answer 673

Manually raise the event by using GetInvocationList

Question 674

Define Sentinal

Answer 674

A value used to signal the end for execution in a loop

Question 675

Define IEnumerable

Answer 675

A code component in C# that supports iterations

Question 676

Name three generic delegate types defined by the .NET framework

Answer 676

Action
Func
Predicate

Question 677

Define contravariance

Answer 677

Returns a value from a superclass of the type expected by the delegate

Question 678

Define covariance

Answer 678

Returns a value from a subclass of the result expected by a delegate

Question 679

Name the steps to implementing a delegate

Answer 679

1. Use the delegate keyword to define delegate type
2. Create variables of delegate type
3. Set variables equal to methods that match delegates and return type
4. Invoke the variable

Question 680

How to declare a delegate

Answer 680

accessModifier delegate returnType DelegateName();

ex
private delegate int FunctionDelegate(float x);

Question 681

What are best practices for naming delegate types

Answer 681

delegate types should end with the suffix Delegate
ex. FunctionDelegate

If a delegate is used as a collback, when code finishes suffix with Callback
ex FunctionCallback

Question 682

Define Action delegates

Answer 682

A method that returns void and accepts between 0 and 18 parameters

Question 683

Define Func delegates

Answer 683

A method that returns a value and accepts between 0 and 18 parameters

Question 684

Provide example of replacing custom delegate with action delegate

Answer 684

private delegate void FunctionDelegate(param)
private FunctionDelegate FunctionParamMethod;

replace with:
private Action FunctionParamMethod;

Question 685

Provide example of replacing custom delegate with Func delegate

Answer 685

private delegate datatype FunctionDelegate(param)
private FunctionDelegate FunctionParamMethod;

replace with:
private Func FunctionParamMethod;

Question 686

In the following code sample, will the second if structure be evaluated?

bool condition = true;
if(condition)
  if( 5 < 10)
  {
    Console.WriteLine("5 is less than 10");
  }

Answer 686

Yes

Question 687

What kind of result is returned in the condition part of an if statement?

Answer 687

bool

Question 688

You need to move a logical comparison where two values must return true in order for your code to execute the correct statement.

What do you do?

Answer 688

&&

Question 689

You want to declare an integer variable called myVar and assign it to the value 0.

How can you accomplish this?

Answer 689

int myVar = 0;

Question 690

If you want to iterate over the values in an array of integers called arrNumbers to perform an action on them, which loop statement enables you to do this?

Answer 690

foreach(int numer in arrNumbers)
{
  // Do Something
}

Question 691

What is the purpose of the break in a switch statement?

Answer 691

It causes the code to exit the switch statement

Question 692

What are the four main repetition structures in C#?

Answer 692

for
foreach
while
do-while

Question 693

How many times will this loop execute?

int value = 0;
do
{
  Console.WriteLine(value);
}while(value > 10);

Answer 693

Once

Question 694

A data type conversion where the destination type can hold all values in the source type is known as ?

Answer 694

Widening conversion

Question 695

What encoding is used by the .NET framework

Answer 695

UTF-16, 16 bits per character

Question 696

Define unicode

Answer 696

A standard for encoding characters used by scripts in various locales around the world

Question 697

What pool holds an instance of every unique string?

Answer 697

The intern pool

Question 698

String values do not change, they are referred to as ?

Answer 698

immutable

Question 699

What is a dynamic type

Answer 699

A static type that is not evaluated until runtime

Question 700

When does unboxing occur?

Answer 700

When converting a reference type to a value type

Question 701

How does boxing occur?

Answer 701

When converting a value type to a reference type

Question 702

What class is used to convert data to and from an array of bytes?

Answer 702

System.BitConverter

Question 703

Name the methods in System.Convert

Answer 703

ToBoolean, ToDouble, ToSingle, ToByte, toInt16, ToString, ToChar, ToInt32, ToInt16, ToDateTime, ToInt64, TUInt32, ToDecimal, ToSByte, ToUInt64

Question 704

What class provides methods that convert from one type to another?

Answer 704

System.Convert

Question 705

Name some common styles from System.Globalization.NumberStyles

Answer 705

Integer
HexNumber
Number
Float
Currency
Any

Question 706

What enumeration allows Parse and TryParse to understand special symbols?

Answer 706

System.Globalization.NumberStyles

Question 707

What method can be used to parse text and see if ther is an error?

Answer 707

TryParse()

Question 708

How is text parsed into values?

Answer 708

using the Parse() method

Question 709

What is the purpose of the as operator?

Answer 709

To convert an object into a compatible type or NULL if compatibility doesn’t exist.

Question 710

What is the purpose of the is operator?

Answer 710

To determine if a variable is compatible with a specific type

Question 711

How are floating point operations checked for overflow or underflow?

Answer 711

By checking the Infinity and/or NegativeInfinity properties

Question 712

How are integer overflows captured?

Answer 712

Using the checked block

or

Advanced Builds Setting Dialog

Question 713

Yes or No

Do explicit conversions require a cast operator?

Answer 713

Yes

Question 714

Yes or No

Do implicit conversions require a cast operator?

Answer 714

No

Question 715

Which technique should you use to watch for floating point operations that cause overflow or underflow conditions?

Answer 715

Check the result for the Infinity or NegativeInfinity

Question 716

Which statement can be used to capture integer overflow or underflow errors?

Answer 716

checked

Question 717

Can the string class space method be used to create a string containing 10 spaces?

Answer 717

No

Question 718

Name three common string methods

Answer 718

IndexOf
StartsWith
Trim
(ther are others)

Question 719

If Employee inherits from Person and Manager inherits from Employee then assign a Person to an Employee type.

Answer 719

Person alex = new Employee();

Question 720

The statement object obj=72 is an example of?

Answer 720

boxing

Question 721

What is the best way to store an integer value typed by the user in a variable?

Answer 721

TryParse

Question 722

If i is an int and l is a long
then i = (int) l

is what ype of conversion?

Answer 722

narrowing conversion

Question 723

Generate a string containing the text “Vend, Vidi, Vici”

Answer 723

String.Format(“{0}, {1},{2}”, “Vend”, “Vidi”, “Vici”);

Question 724

Assuming total is a decimal variable holding the value 1234.56, which of he following statements display total with currency format $1,234.56?

Answer 724

Console.WriteLine( total.ToString(“c”));

Question 725

Name the characteristics of narrowing conversions

Answer 725

The source and destination must be compatible

Question 726

Name the characteristics of widening conversions

Answer 726

Any value of the source type can fit into the destination type

The conversion will not result in loss of magnitude but may result in loss of precision

An explicit cast is optional

Question 727

Why are properties valuable?

Answer 727

To perform data validations on incoming and outgoing data values

Question 728

What operations can be performed on properties?

Answer 728

read/write
read only
write only

Question 729

What is the purpose of properties?

Answer 729

To present the public interface to your class

Question 730

In encapsulation, how is data exposed?

Answer 730

Through properties

Question 731

In encapsulation what access modifier is specified for member variables?

Answer 731

private

Question 732

What is the purpose of encapsulation?

Answer 732

Functionality and data are enclosed as part of the class

Question 733

What is another name for data hiding?

Answer 733

encapsulation

Question 734

What enables you to pass arguments to a method in order other than specified in the message signature?

Answer 734

named parameters

Question 735

What allows for giving parameters in a method a name?

Answer 735

named parameters

Question 736

What are the requirements when using optional parameters?

Answer 736

Must exist after required parameters

If multiple optional parameters exist and a value is specified for one, all preceding optional parameters must also be supplied values

Question 737

When is a default value used?

Answer 737

If none is passed by caller

Question 738

How are optional parameters defined?

Answer 738

By including a default value

Question 739

Name the type of parameters that enable you to choose the parameters required in a method

Answer 739

optional parameters

Question 740

What type of classes are overridden?

Answer 740

Virtual and abstract methods in base classes

Question 741

What type of method provides the means to change method behavior in a derived class?

Answer 741

overriden methods

Question 742

What is the purpose of extension methods?

Answer 742

To extend existing lasses by adding methods without recompiling

Question 743

Where are extension methods applied?

Answer 743

To your own types or existing types in .NET

Question 744

What is the purpose of overridden methods?

Answer 744

To hide the implementation of a method of the same name in the base class

Question 745

Where are abstract methods defined?

Answer 745

Abstract methods can only be defined in abstract classes

Question 746

You are creating a custom Distance class. You want to ease the conversion from your Distance class to a double.

What should you add?

Answer 746

An implicit cast operator

Question 747

What area is used by the .NET compiler to store reference type variables?

Answer 747

heap

Question 748

Variables that store the characteristics data for a class are referred to as?

Answer 748

fields

Question 749

The object that listens for an event to be raised is?

Answer 749

The event subscriber

Question 750

The object that raises the event for the listener or subscriber is the ?

Answer 750

event publisher

Question 751

A distinct type consisting of a set of named constants is known as an ?

Answer 751

enumeration

Question 752

The hiding of details around the implementation of an object so there are no external dependencies on the particular implementation?

Answer 752

encapsulation

Question 753

Components in code that are used to store data within a program are referred to as?

Answer 753

data structures

Question 754

What class methods are executed when an object of a given type is created?

Answer 754

constructors

Question 755

What are coding components that enable you to create custom types to group together characteristics, mehtods and events

Answer 755

classes

Question 756

What is used to encapsulate data and functionality into one unit of code

Answer 756

class files

Question 757

What methods are used to access hidden number variables?

Answer 757

accessor methods

Question 758

When can an abstract modifier be used?

Answer 758

With classes, methods, properties, indexers and events

Question 759

When is an abstract modifier used?

Answer 759

To indicate that a class is intended to be only a base class of other classes

Question 760

What technique is used to define methods without specifying the types for parameters at definition stage?

Answer 760

generic types

Question 761

What is the purpose of the generic type?

Answer 761

Enables type-safe coding

Increase performance due to reduction in conversions, boxing/unboxing.

Question 762

What types are used as a placeholder at define stage that is replaced by type during instantiation?

Answer 762

generic types

Question 763

How are indexed properties accessed?

Answer 763

Using an index in the same manner as arrays

Question 764

What properties allow array like access to group of items?

Answer 764

idexers (indexed properties)

Question 765

What are instance fields?

Answer 765

fields related to a specific instance. Values are not shared among objects of the same class.

Question 766

You are using an ArrayList as a collection for a list of points, which are a custom struct. You are experiencing performance problems when working with a large amount of points.

What do yo have to do?

Answer 766

Use a generic collection instead of ArrayList

Question 767

Define properties

Answer 767

Members that provide a flexible mechanixm to read, write or compute the values of private fields.

Question 768

When is the override access method used?

Answer 768

To extend or modify the abstract or virtual implementation of an inherited method, property, indexer or event.

Question 769

What is the purpose of the modifier?

Answer 769

Modify declarations of types and type members

Question 770

What is used to provide functionality for a class?

Answer 770

method

Question 771

What is a memory address?

Answer 771

An addressable location in computer memory used to store and retrieve values

Question 772

You want to determine whether the value of an object reference is derived from a particular type.

Which C# feature can you use?

Answer 772

An as operator

An is operator

Question 773

To parse a string that might contain a currency value such as $1,234.56 you should pass the Parse or TryParse method which of the following values?

Answer 773

NumberStyles.Currency

Question 774

An area of memory used by the .NET compiler to store value types during program execution is known as the?

Answer 774

Stack

Question 775

Methods with identical names for procedures that operate on different data types are referred to as ?

Answer 775

overloaded methods

Question 776

The unique identifying components of a method, such as return type, name and parameter is known as it’s?

Answer 776

signature

Question 777

class files or other objects represented as references to the actual data (memory address) are referred to as ?

Answer 777

reference types

Question 778

In entity framework, which class is responsible for maintaining the bridge between a database engine and C# code?

Answer 778

DbContext

Question 779

Which method is used to return a specific number of objects from a quuery result?

Answer 779

Take()

Question 780

Which of collection types is used to retrieve data in a Last-In, Last-Out (LIFO) way?

Answer 780

Stack

Question 781

What keyworkd is used to filter a query?

Answer 781

Where()

Question 782

Which extension method is used to join two queries?

Answer 782

join()

Question 783

Suppose you’re writing a method that retrieves the data from an MS Access 2013 database. The method must meet the following requirements;

1. Be read-only
2. Be able to use the data before the entire data set is retrieved
3. Minimize the amount of system overhead and amount of memory usage

What type of object should be used in the method?

Answer 783

Because MS Access

OleDbDataReader

Question 784

Suppose you have the following code segment:

1. ArrayList arrays = new ArrayList();
2. int i = 10 ;
3. int j;
4. arrays.Add(i);
5. j = arrays[0];

You need to resolve the error that occurs at line 05 (“Cannot implicitly convert type object to int”). You need to ensure that the error gets removed.

Which code should you replace in line 05?

Answer 784

j = (int)arrays[0];

Question 785

Suppose you have the following code snippet:
01. class Person
02. {
03. public int ID { get; set; }
04. public string Name { get; set; }
05. public int Age { get; set; }
06. }
07. Dictionary people = new Dictionary
08. {
09. {21, new Person {ID = 1, Name="Ali", Age = 22 } },
10. {22, new Person {ID = 2, Name="Sundus", Age = 21 } },
11. {23, new Person {ID = 3, Name="Asad", Age = 22 } },
12. {24, new Person {ID = 5, Name="Naveed", Age = 21 } },
13. };
14.
15. people.Add(24, new Person { ID = 6, Name = "Malik", Age = 10 });

The application fails at line 15 with the following error message: “An item with the same key has already
been added.” You need to resolve the error.

Which code segment should you insert at line 14?
A) if(!people.ContainsKey(24))
B) foreach (Person person in people.Values.Where(t=>t.ID !=24))
C) foreach (KeyValuePair key in people.Where(t=>t.Key != 24))
D) foreach (int key in people.Keys.Where(k=>k!=24))

Answer 785

A) if(!people.ContainsKey(24))

Question 786

You’re creating an application that counts the number of times a specific word appears in a text file. See the
following code snippet:
01. class Demo
02. {
03. ConcurrentDictionary words =
04. new ConcurrentDictionary();
05. public Action ProcessDir()
06. {
07. Action act = (dirInfo =>
08. {
09. var files = dirInfo.GetFiles("*.cs").AsParallel();
10. files.ForAll(
11. fileinfo =>
12. {
13. var content = File.ReadAllText(fileinfo.FullName);
14. var sb = new StringBuilder();
15. foreach (var item in content)
16. {
17. sb.Append(char.IsLetter(item) ?
18. item.ToString().ToLowerInvariant() : " ");
19. }
20. var wordlist= sb.ToString().Split(new[] { ' ' },
21. StringSplitOptions.RemoveEmptyEntries);
22. foreach (var word in wordlist)
23. {
24.
25. }
26. });
27. var dir = dirInfo.GetDirectories()
28. .AsParallel();
29. dir.ForAll(ProcessDir());
30. });
31. return act;
32. }
33. }

You need to populate a words object with the list of words and the number of occurrences of each word,
and also ensure that the updates to the ConcurrentDictionary object can happen in parallel. Which code
segment should you insert at line 24?

A) words.AddOrUpdate(word, 1, (s, n) => n + 1);
B)
 int value;
 if(words.TryGetValue(word, out value))
 {
 words[word] = value++;
 }
 else
 {
 words[word] = 1;
 }

Answer 786

A) words.AddOrUpdate(word, 1, (s, n) => n + 1);

Question 787

You have a List object that is generated by executing the following code:
List subjects = new List()
{
“English”,”Computer”,”Maths”,”Physics”
};
You have a method that contains the following code:
01. bool GetSameSubjs(List subj, string searchSubj)
02. {
03. var findSubj = subj.Exists((delegate (string subjName)
04. {
05. return subjName.Equals(searchSubj);
06. }
07. ));
08. return findSubj;
09. }
You need to alter the method to use a lambda statement. How should you rewrite lines 03 through 06 of
the method?
A) var findSubj = subj.First(x => x == searchSubj);
B) var findSubj = subj.Where(x => x == searchSubj);
C) var findSubj = subj.Exists(x => x.Equals(searchSubj));
D) var findSubj = subj.Where(x => x.Equals(searchSubj));

Answer 787

C) var findSubj = subj.Exists(x => x.Equals(searchSubj));

Question 788

Which of the following two interfaces should you use to iterate over a collection and release the unmanaged
resources.
A) IEquatable
B) IEnumerable
C) IDisposable
D) IComparable

Answer 788

B) IEnumerable

C) IDisposable

Question 789

You are creating an application that will parse a large amount of text. You need to parse the text into separate
lines and minimize memory use while processing data. Which object type should you use?

A) DataContractSerializer
B) StringBuilder
C) StringReader
D) JsonSerializer

Answer 789

B) StringBuilder

Question 790

You need to store the values in a collection. The values must be stored in the order that they were added to
the collection. The values must be accessed in a first-in, first-out order.

Which type of collection should you use?
A) SortedList
B) Queue
C) ArrayList
D) Hashtable

Answer 790

B) Queue

Question 791

You need to choose a collection type which internally stores a key and a value for each collection item,
provides objects to iterators in ascending order based on the key, and ensures that items are accessible by a
zero-based index or by key. Which collection type should you use?

A) SortedList
B) Queue
C) Array
D) HashTable

Answer 791

A) SortedList

Question 792

You are creating an application that uses a class named Person. The class is decorated with the
DataContractAttribute attribute. The application includes the following code snippet:
01. MemoryStream WritePerson(Person person)
02. {
03. var ms = new MemoryStream();
04. var binary = XmlDictionaryWriter.CreateBinary(ms);
05. var ser = new DataContractSerializer(typeof(Person));
06. ser.WriteObject(binary, person);
07.
08. return ms;
09. }
You need to ensure that the entire Person object is serialized to the memory stream object. Which code
segment should you insert at line 07?
A) binary.WriteEndDocument();
B) binary.WriteEndDocumentAsync();
C) binary.WriteEndElementAsync();
D) binary.Flush();

Answer 792

A) binary.WriteEndDocument();

Question 793

You are developing a class named Person. See the following code snippet:
01. class People
02. {
03. Dictionary people = new Dictionary();
04. public void Add(string name, int age)
05. {
06. people.Add(name, age);
07. }
08.
09. }
It has the following unit test:
 public void UnitTest1()
 {
 People people = new People();
 people.Add("Ali", 22);
 people.Add("Sundus", 21);
 int expectedAge = 21;
 int actualAge = people["Sundus"];
 Assert.AreEqual(expectedAge, actualAge);
 }
You need to ensure the unit test will pass. What code snippet you should insert at line 08?
A)
 public Dictionary People
 {
 get { return people; }
 }
B)
 public int this[string name]
 {
 get
 {
 return people[name];
 }
 }
C)
 public Dictionary People = new Dictionary();
D)
 public int salary(string name)
 {
 return people[name];
 }

Answer 793

B)
 public int this[string name]
 {
 get
 {
 return people[name];
 }
 }

Question 794

You’re creating an application that converts data into multiple output formats; it includes the following code
snippets.
01. class TabDelimitedFormatter : IFormatter
02. {
03. readonly Func suffix =
04. col => col % 2 == 0 ? ‘\n’ : ‘\t’;
05. public string Output(IEnumerator iterator, int size)
06. {
07.
08. }
09. }
10. interface IFormatter
11. {
12. string Output(IEnumerator iterator, int size);
13. }
You need to minimize the completion time of the GetOutput() method. Which code segment should
you insert at line 07?
A)
string output = null;
for(int i = 1; iterator.MoveNext(); i++)
{
output = string.Concat(output, iterator.Current, suffix(i));
}
B)
var output = new StringBuilder();
for(int i = 1; iterator.MoveNext(); i++)
{
output.Append(iterator.Current);
output.Append(suffix(i));
}
C)
string output = null;
for(int i = 1; iterator.MoveNext(); i++)
{
output = output + iterator.Current + suffix(i);
}
D)
string output = null;
for(int i = 1; iterator.MoveNext(); i++)
{
output += iterator.Current + suffix(i);
}

Answer 794

B)
 var output = new StringBuilder();
 for(int i = 1; iterator.MoveNext(); i++)
 {
 output.Append(iterator.Current);
 output.Append(suffix(i));
 }

Question 795

Suppose you’re writing a method named ReadFile that reads data from a file. You must ensure that the
ReadFile method meets the following requirements:
1. It must not make changes to the data file.
2. It must allow other processes to access the data file. It must not throw an
exception if the application attempts to open a data file that does not exist.
Which code segment should you use?
A) var fs = File.Open(Filename, FileMode.OpenOrCreate, FileAccess.Read,
FileShare.ReadWrite);
B) var fs = File.Open(Filename, FileMode.Open, FileAccess.Read, FileShare.
ReadWrite);
C) var fs = File.Open(Filename, FileMode.OpenOrCreate, FileAccess.Read,
FileShare.Write);
D) var fs = File.ReadAllLines(Filename);
E) var fs = File.ReadAllBytes(Filename);

Answer 795

A) var fs = File.Open(Filename, FileMode.OpenOrCreate, FileAccess.Read,
FileShare.ReadWrite);

Question 796

You’re using ADO.NET Entity Framework to retrieve data from a database in MS SQL Server. Suppose you
have the following code snippet:
01. public DataTime? OrderDate;
02. IQueryable GetOrderByYear(int year)
03. {
04. using (var context = new NortwindEntities())
05. {
06. var orders = from order in context.Orders;
07.
08. select order;
09. return orders.ToList().AsQueryable();
10. }
11. }
You need to ensure the following requirements:
1. Return only orders that have an OrderDate value other than null.
2. Return only orders that were placed in the year specified in the OrderDate
property or in a later year.
Which code segment should you insert at line 07?
A) Where order.OrderDate.Value != null && order.OrderDate.Value.Year > = year
B) Where order.OrderDate.Value = = null && order.OrderDate.Value.Year = = year
C) Where order.OrderDate.HasValue && order.OrderDate.Value.Year = = year
D) Where order.OrderDate.Value.Year = = year

Answer 796

A) Where order.OrderDate.Value != null && order.OrderDate.Value.Year > = year

Question 797

An application has the following code:
01. class Person
02. {
03. public string Name { get; set; }
04. public int Age { get; set; }
05. }
06. static IEnumerable GetPersons(string sqlConnectionString)
07. {
08. var people = new List();
09. SqlConnection sqlConnection = new SqlConnection(sqlConnectionString);
10. using (sqlConnection)
11. {
12. SqlCommand sqlCommand = new SqlCommand(“Select Name, Age From
13. Persons”, sqlConnection);
14.
15. using (SqlDataReader sqlDataReader = sqlCommand.ExecuteReader())
16. {
17.
18. {
19. Person person = new Person();
20. person.Name = (string)sqlDataReader[“Name”];
21. person.Age = (int)sqlDataReader[“Age”];
22.
23. people.Add(person);
24. }
25. }
26. }
27. return people;
28. }
The GetPersons() method must meet the following requirements:
1. Connect to a Microsoft SQL Server database.
2. Create Animal objects and populate them with data from the database.
Which two actions should you perform?
A) Insert the following code segment at line 17:
while(sqlDataReader.NextResult())
B) Insert the following code segment at line 14:
sqlConnection.Open();
C) Insert the following code segment at line 14:
sqlConnection.BeginTransaction();
D) Insert the following code segment at line 17:
while(sqlDataReader.Read())
E) Insert the following code segment at line 17:
while(sqlDataReader.GetValues())

Answer 797

B) Insert the following code segment at line 14:
sqlConnection.Open();
C) Insert the following code segment at line 14:
sqlConnection.BeginTransaction();

Question 798

Suppose you have a collection of integer values. You define an integer variable named IntegerToRemove and
assign a value to it. You declare an array named filteredIntegers. You must to do the following things.
Remove duplicate integers from the integer array. Sort the array in order from the highest value to the
lowest value. Remove the integer value stored in the integerToRemove variable from the integers array.
Which LINQ query would you need to create to meet the requirements?
A)
int[] filteredIntegers = integers.Where(value => value !=
integerToRemove).OrderBy(x => x).ToArray();
B)
int[] filteredIntegers = integers.Where(value => value !=
integerToRemove).OrderByDescending(x => x).ToArray();
C)
int[] filteredIntegers = integers.Distinct().Where(value => value !=
integerToRemove).OrderByDescending(x => x).ToArray();
D)
int[] filteredIntegers = integers.Distinct()
.OrderByDescending(x => x).ToArray();

Answer 798

C)
int[] filteredIntegers = integers.Distinct().Where(value => value !=
integerToRemove).OrderByDescending(x => x).ToArray();

Question 799

Suppose you’re creating an application that includes the following code, which retrieves JSON data. You
need to ensure that the code validates the JSON.
01. bool ValidateJSON(string json, Dictionary result)
02. {
03.
04. try
05. {
06. result = serializer.Deserializer>(json);
07. return true;
08. }
09. catch
10. {
11. return false;
12. }
13. }

Which code should you insert at line 03?
A) var serializer = new DataContractSerializer();
B) DataContractSerializer serializer = new DataContractSerializer();
C) var serializer = new XmlSerializer();
D) var serializer = new JavaScriptSerializer();

Answer 799

D) var serializer = new JavaScriptSerializer();

Question 800

Suppose you have a List people = new List(); You need to create an extension method that
will return the correct number of Person objects from the people list that can be displayed on each page and
each page has a uniform page size. Which code snippet should you use?
A)
 Public static IEnumerable Page(IEnumerable source, int page, int pagesize)
 {
 return source.Take((pagesize - 1) * page).Skip(pagesize);
 }
B)
 Public static IEnumerable Page(this IEnumerable source, int page, int pagesize)
 {
 return source.Skip((page - 1) * pagesize).Take(pagesize);
 }
C)
 static IEnumerable Page(IEnumerable source, int page, int pagesize)
 {
 return source.Skip((pagesize - 1) * page).Take(pagesize);
 }
D)
 Public static IEnumerable Page(this IEnumerable source, int page, int pagesize)
 {
 return source.Take((page - 1) * pagesize).Skip(pagesize);
 }

Answer 800

B)
Public static IEnumerable Page(this IEnumerable source, int page, int pagesize)
{
return source.Skip((page - 1) * pagesize).Take(pagesize);
}

Question 801

Suppose you’re developing an application that needs to read the data from a file and then release the file
resources. Which code snippet should you use?
A)
 string data;
 using (StreamReader readfile = new StreamReader("data.txt"))
 {
 while ((data = readfile.ReadLine()) != null)
 {
 Console.WriteLine(data);
 }
 }
B)
 string data;
 StreamReader readfile = null;
 using ( readfile = new StreamReader("data.txt"))
 {
 while ((data = readfile.ReadLine()) != null)
 {
 Console.WriteLine(data);
 }
 }
C)
 string data;
 StreamReader readfile = new StreamReader("data.txt");
 while ((data = readfile.ReadLine()) != null)
 {
 Console.WriteLine(data);
 }
D)
 string data;
 StreamReader readfile = null;
 try
 {
 readfile = new StreamReader("data.txt");
 while ((data = readfile.ReadLine()) != null)
 {
 Console.WriteLine(data);
 }
 readfile.Close();
 readfile.Dispose();
 }
 finally
 {
 }

Answer 801

A)
 string data;
 using (StreamReader readfile = new StreamReader("data.txt"))
 {
 while ((data = readfile.ReadLine()) != null)
 {
 Console.WriteLine(data);
 }
 }

Question 802

Suppose you are developing an application that includes the following code:
List list = new List
{
 80,
 75,
 60,
 55,
 75
};
You have to retrieve all the numbers that are greater than 60 from a list. Which code should you use?
A)
 var result = from i in list
 where i > 60
select i;
B)
 var result = list.Take(60);
C)
 var result = list.First(i => i > 80);
D)
 var result = list.Any(i => i > 80);

Answer 802

A)
var result = from i in list
where i > 60
select i;

Question 803

You want to configure your application to output more trace data. What would you use for the configuration
setting?
A) Listener
B) Filter
C) Switch
D) Trace

Answer 803

C) Switch

Question 804

You are developing an assembly that will be used by server applications. You want to make the update
process of this assembly as smooth as possible. What steps would you take?
A) Create WinMD Assembly
B) Deploy Assembly to GAC
C) Sign the assembly with the storing name
D) Delay sign the assembly

Answer 804

B) Deploy Assembly to GAC

Question 805

You need to send your data to a receiver and want no one to tamper with your data. What would you use?
A) X509Certificate2.SignHash
B) RSACryptoServiceProvider.Enrypt
C) UnicodeEncoding.GetBytes
D) Marshal.ZeroFreeBSTR

Answer 805

A) X509Certificate2.SignHash

C) UnicodeEncoding.GetBytes

Question 806

You need to validate an XML file. What would you use?
A) XSD
B) RegEx
C) StringBuilder
D) JavaScriptSerializer

Answer 806

A) XSD

Question 807

Which method is easiest to find the problem if you have no idea what it is?
A) Using Profiler
B) Profiling by Hand
C) Using Performance Counter
D) Debugging

Answer 807

A) Using Profiler

Question 808

To build a project you need a PDB file of:
A) Previous build version
B) Any build version
C) Current Solution File
D) Same build version

Answer 808

D) Same build version

Question 809

Which class should preferably be used for tracing in Release Mode?
A) Debug
B) Trace
C) TraceSource
D) All of the above

Answer 809

C) TraceSource

Question 810

Which bindingflags are useful for getting the private data instance?
A) BindingFlags.NonPublic | BindingFlags.Instance
B) BindingFlags.Private | BindingFlags.Instance
C) BindingFlags.NonPrivate | BindingFlags.NonStatic
D) BindingFlags.Private | BindingFlags.NonStatic

Answer 810

A) BindingFlags.NonPublic | BindingFlags.Instance

Question 811

Which of the following methods is used for getting the information of a current assembly?
A) Assembly. GetExecutingAssembly();
B) Assembly.GetExecutedAssembly();
C) Assembly.GetCurrentAssembly();
D) Assembly.ExecutingAssembly();

Answer 811

A) Assembly. GetExecutingAssembly();

Question 812

Which of the following commands is required to create a strong name key?
A) sn -k {assembly_name}.snk
B) sn k {assembly_name}.snk
C) gacutil -i {assembly_name}.snk
D) gacutil i {assembly_name}.snk

Answer 812

A) sn -k {assembly_name}.snk

Question 813

Salt Hashing is done by:
A) Merging data with a random value and performing Cryptography
B) Merging data with a random value and performing Cryptanalysis
C) Merging data with a random value and performing Encryption
D) Merging data with a random value and performing Hashing

Answer 813

D) Merging data with a random value and performing Hashing

Question 814

You are developing an application which transmits a large amount of data. You need to ensure the data
integrity. Which algorithm should you use?
A) RSA
B) HMACSHA256
C) Aes
D) RNGCryptoServiceProvider

Answer 814

B) HMACSHA256

Question 815

The application needs to encrypt highly sensitive data. Which algorithm should you use?
A) DES
B) Aes
C) TripleDES
D) RC2

Answer 815

B) Aes

Question 816

How would you throw an exception to preserve stack-trace information?
A) throw;
B) throw new Exception();
C) throw e;
D) return new Exception();

Answer 816

A) throw;

Question 817

You need to validate a string which has numbers in 333-456 format. Which pattern should you choose?
A) @"\d\d-\d\d"
B) @"\n{3}-\n{3}"
C) @"[0-9]+-[0-9]"
D) @"\d{3}-\d{3}"

Answer 817

D) @”\d{3}-\d{3}”

Question 818

You are required to install an assembly in GAC. Which action should you take?
A) Use the Assembly Registration tool (regasm.exe)
B) Use the strong name tool (sn.exe)
C) User Microsoft register server (regsvr32.exe)
D) Use the Global Assembly Cache tool (gacutil.exe)
E) Use Windows installer 2.0

Answer 818

D) Use the Global Assembly Cache tool (gacutil.exe)

E) Use Windows installer 2.0

Question 819

You have the following code snippet:
If(! PerformanceCounterCategory.Exists(“CounterExample”))
{
Var counters=new CounterCreationDataCollection();
Var counter1=new CounterCreationData
{
CounterName=”Counter1”,
CounterType=PerformanceCounterType.SampleFraction
};
Var counter2=new CounterCreationData
{
CounterName=”Counter2”
};
Counters.Add(counter1);
Counters.Add(counter2);
PerformanceCounterCategory.Create(“CounterExample”,””,PerformanceCounterCategoryType.
MultiInstance,counters);
}
You need to ensure that counter1 is available for performance monitor. Which code segment should
you use?
A) CounterType=PerformanceCounterType.RawBase
B) CounterType=PerformanceCounterType.AverageBase
C) CounterType=PerformanceCounterType.SampleBase
D) CounterType=PerformanceCounterType.CounterMultiBase

Answer 819

C) CounterType=PerformanceCounterType.SampleBase

Question 820

You have to class ExceptionLogger and its method LogExecption, which logs the exception. You need to log
all exceptions that occur and rethrow the original, including the entire exception stack.
Which code segment should you use for the above requirements?
A) Catch(Exception ex)
 {
 ExceptionLogger.LogException(ex);
 throw;
 }
B) Catch(Exception ex)
 {
 ExceptionLogger.LogException(ex);
 throw ex;
 }

C) Catch(Exception)
 {
 ExceptionLogger.LogException();
 throw;
 }
D) Catch(Exception )
 {
 ExceptionLogger.LogException(ex);
 throw ex;
 }

Answer 820

A) Catch(Exception ex)
 {
 ExceptionLogger.LogException(ex);
 throw;
 }

Question 821

You are required to create an event source named mySource and a custom log named myLog on the server.
You need to write the “Hello” information event to the custom log.
Which code segment should you use?
A) EventLog Log=new EventLog(){Source=”mySource”};
Log.WriteEntry(“Hello”,EventLogEntryType.Information);
B) EventLog Log=new EventLog(){Source=”myLog”};
Log.WriteEntry(“Hello”,EventLogEntryType.Information);
C) EventLog Log=new EventLog(){Source=”System”};
Log.WriteEntry(“Hello”,EventLogEntryType.Information);
D) EventLog Log=new EventLog(){Source=”Application”};
Log.WriteEntry(“Hello”,EventLogEntryType.Information);

Answer 821

A) EventLog Log=new EventLog(){Source=”mySource”};
 Log.WriteEntry(“Hello”,EventLogEntryType.Information);

Question 822

You are required to create a program with the following requirements:
In Debug Mode, console output must display Entering Release Mode.
In Release Mode, console output must display Entering Debug Mode.
Which code segment should you use?
A) if DEBUG.DEFINED
Console.WriteLine(“Entering Release Mode”);
else
Console.WriteLine(“Entering Debug Mode”);

B) if RELEASE.DEFINED
Console.WriteLine(“Entering Debug Mode”);
else
Console.WriteLine(“Entering Release Mode”);
C) #if DEBUG
Console.WriteLine(“Entering Release Mode”);
#elif RELEASE
Console.WriteLine(“Entering Debug Mode”);
D) #if DEBUG
Console.WriteLine(“Entering Debug Mode”);
#elif RELEASE
Console.WriteLine(“Entering Release Mode”);

Answer 822

C) #if DEBUG
Console.WriteLine(“Entering Release Mode”);
#elif RELEASE
Console.WriteLine(“Entering Debug Mode”);

Question 823

You are creating a library (.dll file) for your project. You need to make it a strongly typed assembly. What
should you do?
A) use the csc.exe/target:Library option when building the application
B) use the AL.exe command line-tool
C) use the aspnet_regiis.exe command line-tool
D) use the EdmGen.exe command line-tool

Answer 823

B) use the AL.exe command line-tool

Question 824

You are required to create a class “Load” with the following requirements:
Include a member that represents the rate of a Loan instance.
Allow an external code to assign a value to a rate member.
Restrict the range of values that can be assigned to the rate member.
To meet these requirements, how would you implement the rate member?
A) public static property
B) public property
C) public static field
D) protected field

Answer 824

B) public property

Question 825

You are required to develop a method which can be called by a varying number of parameters. The method
is called:
A) Method Overriding
B) Method Overloading
C) Abstract Method
D) Virtual Method

Answer 825

B) Method Overloading

Question 826

You are working on an application where you need to encrypt highly sensitive data. Which algorithm should
you use?
A) DES
B) Aes
C) TripleDES
D) RC2

Answer 826

B) Aes

Question 827

You need to create a unique identity for your application assembly. Which two attributes should you include
for this purpose?
A) AssemblyTitleAttribute
B) AssemblyCultureAttribute
C) AssemblyVersionAttribute
D) AssemblyKeyNameAttribute
E) AssemblyFileVersion

Answer 827

B) AssemblyCultureAttribute

C) AssemblyVersionAttribute

Question 828

Which statement is used to remove the unnecessary resources automatically?
A) using
B) switch
C) Uncheck
D) Check

Answer 828

A) using

Question 829

Which class is necessary to inherit while creating a custom attribute?
A) Exception
B) Attribute
C) Serializable
D) IEnumerable

Answer 829

B) Attribute

Question 830

Which of the following interfaces is used to manage an unmanaged resource?
A) IUnkown
B) IEnumerable
C) IComparable
D) IDisposable

Answer 830

D) IDisposable

Question 831

Which of the following interfaces is necessary to implement for creating a custom collection in C#?
A) IUnkown
B) IEnumerable
C) IComparable
D) IDisposable

Answer 831

B) IEnumerable

Question 832

How would you parse a type to another in a way that it doesn’t generate an exception in a wrong conversion?
A) as
B) is
C) out
D) in

Answer 832

A) as

Question 833

Which keyword is used to check or compare one type to another?
A) as
B) is
C) out
D) in

Answer 833

B) is

Question 834

How should you create an extension method of an integer?
A)
 static class ExtensionClass
 {
 public static void ExtensionMethod(this int i)
 {
 //do code
 }
 }
B)
 static class ExtensionClass
 {
 public static void ExtensionMethod(int i)
 {
 //do code
 }
 }

C)
 class ExtensionClass
 {
 public static void ExtensionMethod(this int i)
 {
 //do code
 }
 }
D)
 static class ExtensionClass
 {
 public void ExtensionMethod(this int i)
 {
 //do code
 }
 }

Answer 834

A)
 static class ExtensionClass
 {
 public static void ExtensionMethod(this int i)
 {
 //do code
 }
 }

Question 835

What should you use to encapsulate an array object?
A) Indexer
B) Property
C) Event
D) Private array

Answer 835

A) Indexer

Question 836

Which of the following keywords is used for a dynamic variable?
A) var
B) dynamic
C) const
D) static

Answer 836

B) dynamic

Question 837

Which of the following methods of assembly is used to get all types?
A) GetTypes()
B) GetType()
C) ToTypeList()
D) Types()

Answer 837

A) GetTypes()

Question 838

How would you make sure the garbage collector does not release the object’s resources until the process
completes? Which garbage collector method should you use?
A) WaitForFullGCComplete()
B) SuppressFinalize()
C) collect()
D) RemoveMemoryPressure()

Answer 838

B) SuppressFinalize()

Question 839

You are developing an application that includes the following code segment:
01. class A { }
02. class B : A { }
03. class C
04. {
05. void Demo(object obj)
 { 
  Console.WriteLine("Demo(obj)");
}
06. void Demo(C c) { Console.WriteLine("Demo(C)");}
07. void Demo(A a) { Console.WriteLine("Demo(A)");}
08. void Demo(B b) { Console.WriteLine("Demo(B)");}
09.
10. void Start()
11. {
12. object o = new B();
13. Demo(o);
14. }
15. }
You need to ensure that the Demo(B b) method runs. With which code segment should you replace
line 13?
A) Demo((B)o);
B) Demo(new B(o));
C) Demo(o is B);
D) Demo((A)o);

Answer 839

A) Demo((B)o);

Question 840

How would you ensure that the class library assembly is strongly named? What should you do?
A) Use the gacutil.exe command-line tool.
B) Use the xsd.exe command-line tool.
C) Use the aspnet_regiis.exe command-line tool.
D) Use assembly attributes.

Answer 840

D) Use assembly attributes.

Question 841

Suppose you are developing an application that includes an object that performs a long-running process.
You need to ensure that the garbage collector does not release the object’s resources until the process
completes.
Which garbage collector method should you use?
A) WaitForFullGCComplete()
B) WaitForFullGCApproach()
C) KeepAlive()
D) WaitForPendingFinalizers()

Answer 841

C) KeepAlive()

Question 842

You need to convert a date value entered in string format and you need to parse it into DateTime and convert
it to Coordinated Universal Time (UTC). The code must not cause an exception to be thrown. Which code
segment should you use?
A)
 string strDate = "";
 bool ValidDate = DateTime.TryParse(strDate,
 CultureInfo.CurrentCulture,
 DateTimeStyles.AdjustToUniversal | DateTimeStyles.AssumeLocal,
 out ValidatedDate);
B)
 string strDate = "";
 bool ValidDate = DateTime.TryParse(strDate,
 CultureInfo.CurrentCulture,
 DateTimeStyles.AssumeLocal,
 out ValidatedDate);
C)
 bool validDate = true;
 try
 {
 ValidatedDate = DateTime.Parse(strDate);
 }
 catch
 {
 validDate = false;
 }

Answer 842

A)
string strDate = “”;
bool ValidDate = DateTime.TryParse(strDate,
CultureInfo.CurrentCulture,
DateTimeStyles.AdjustToUniversal | DateTimeStyles.AssumeLocal,
out ValidatedDate);

Question 843

How would you convert the following values?
01. float ft;
02. object o = ft;
03.
04. Console.WriteLine(i);
You need to ensure that the application does not throw exceptions on invalid conversions. Which code
segment should you insert at line 03?
A) int i = (int)(float)o;
B) int i = (int)o;
C) int i = o;
D) int i = (int)(double)o;

Answer 843

A) int i = (int)(float)o;

Question 844

You are creating a class named Person. The class has a string property named FirstName.
01. class Person
02. {
03. public string FirstName
04. {
05. get;
06. set;
07. }
08. }
The FirstName property value must be accessed and modified only by code within the Person class or
within a class derived from the Person class.
Which two actions should you perform?
A) Replace line 05 with the protected get;
B) Replace line 06 with the private set;
C) Replace line 03 with the public string EmployeeType
D) Replace line 05 with the private get;
E) Replace line 03 with the protected string EmployeeType
F) Replace line 06 with the protected set;

Answer 844

B) Replace line 06 with the private set;

E) Replace line 03 with the protected string

Question 845

Suppose you’re creating an application that concatenates “1” value with a string for a million times. Which
of the following codes would you use that minimize the completion time and concatenates the string for the
millionth time?
A)
 string str = "";
 for (int i = 0; i < 1000000; i++)
 {
 str = string.Concat(str, "1");
 }
 return str;
B)
 var str = new StringBuilder();
 for (int i = 0; i < 1000000; i++)
 {
 str.Append("1");
 }
 return str.ToString();
C)
 var str = null;
 for (int i = 0; i < 1000000; i++)
 {
 str = str + "1";
 }
 return str.ToString();
D)
 var str = null;
 for (int i = 0; i < 1000000; i++)
 {
 str += "1";
 }
 return str.ToString();

Answer 845

B)
 var str = new StringBuilder();
 for (int i = 0; i < 1000000; i++)
 {
 str.Append("1");
 }
 return str.ToString();

Question 846

Suppose you are developing an application that includes classes named Car and Vehicle and an interface
named IVehicle. The Car class must meet the following requirements:
It must either inherit from the Vehicle class or implement the IVehicle interface. It must be inheritable
by other classes in the application. You need to ensure that the Car class meets the requirements.
Which two code segments can you use to achieve this goal?
A)
sealed class Car : Vehicle
{
…
}
B)
abstract class Car: Vehicle
{
…
}

C)
sealed class Car : IVehicle
{
 ...
}
D)
abstract class Car : IVehicle
{
}

Answer 846

B)
abstract class Car: Vehicle
{
 ...
}

D)
abstract class Car : IVehicle
{
}

Question 847

Suppose you are creating an application that manages the information of persons. The application includes
a class named Person and a method named Save. The Save() method must be strongly typed. It must allow
only types inherited from the Person class that use a constructor that accepts no parameters.
You need to implement the Save() method. Which code segment should you use?
A)
public static void Save(T target) where T: new(), Person
{
…
}
B)
public static void Save(T target) where T: Person
{
…
}
C)
public static void Save(T target) where T: Person, new()
{
…
}
D)
public static void Save(Person person)
{
…
}

Answer 847

C)
 public static void Save(T target) where T: Person, new()
 {
 ...
 }

Question 848

Suppose you are developing an application that uses the following C# code:
01. public interface IPerson
02. {
03. string Name { get; set; }
04. }
05.
06. void Demo(object obj)
07. {
08.
09. if(person != null)
10. {
11. System.Console.WriteLine(person.Name);
12. }
13. }
The Demo() method must not throw any exceptions when converting the obj object to the IPerson
interface or when accessing the Data property. You need to meet the requirements. Which code segment
should you insert at line 08?
A) var person = (IPerson)obj;
B) dynamic person = obj;
C) var person = obj is IPerson;
D) var person = obj as IPerson;

Answer 848

D) var person = obj as IPerson;

Question 849

You are developing an application. The application converts a Person object to a string by using a
method named WriteObject. The WriteObject() method accepts two parameters: a Person object and an
XmlObjectSerializer object.
The application includes the following code:
01. public enum Gender
02. {
03. Male,
04. Female,
05. Others
06. }
07. [DataContract]
08. public class Person
09. {
10. [DataMember]
Chapter 16 ■ Practice Exam Questions
434
11. public string Name { get; set; }
12. [DataMember]
13. public Gender Gender { get; set; }
14. }
15. void Demo()
16. {
17. var person = new Person { Name = "Ali", Gender = Gender.Male };
18. Console.WriteLine(WriteObject(person,
19.
20. ));
21. }
You need to serialize the Person object as a JSON object. Which code segment should you insert at line 19?
A) new DataContractSerializer(typeof(Person))
B) new XmlSerializer(typeof(Person))
C) new NetDataContractSenalizer()
D) new DataContractJsonSerializer(typeof(Person))

Answer 849

D) new DataContractJsonSerializer(typeof(Person))

Question 850

You’re creating an application that receives a JSON data in the following format:
{
“Name” : “Ali”,
“Age” : “22”,
“Languages”: [“Urdu”, “English”]
}
The application includes the following code segment:
01. public class Person
02. {
03. public string Name { get; set; }
04. public int Age { get; set; }
05. public string[] Languages { get; set; }
06. }
07. public static Person ConvertToPerson(string json)
08. {
09. var ser = new JavaScriptSerializer();
10.
11. }
You need to ensure that the ConvertToName() method returns the JSON input string as a Name object.
Which code segment should you insert at line 10?
A) Return ser.ConvertToType(json);
B) Return ser.DeserializeObject(json);
C) Return ser.Deserialize(json);
D) Return (Person)ser.Serialize(json);

Answer 850

C) Return ser.Deserialize(json);

Question 851

You are developing an application that includes the following code segment:
 interface ILion
 {
 void Run();
 }
 interface IMan
 {
 void Run();
 }

You need to implement both Run() methods in a derived class named Animal that uses the Run()
method of each interface.
Which two code segments should you use?
A)
 var animal = new Animal();
 ((ILion, IMan)animal).Run();
B)
 class Animal : ILion, IMan
 {
 public void IMan.Run()
 {
 ...
 }
 public void ILion.Run()
 {
 ...
 }
 }
C)
 class Animal : ILion, IMan
 {
 void IMan.Run()
 {
 ...
 }
 void ILion.Run()
 {
 ...
 }
 }
D)
 var animal = new Animal();
 ((ILion)animal).Run();
 ((IMan)animal).Run();
E)
 var animal = new Animal();
 animal.Run(ILion);
 animal.Run(IMan);
F)
 var animal = new Animal();
 animal.Run();

Answer 851

B)
 class Animal : ILion, IMan
 {
 public void IMan.Run()
 {
 ...
 }
 public void ILion.Run()
 {
 ...
 }
 }

D)
var animal = new Animal();
((ILion)animal).Run();
((IMan)animal).Run();

Question 852

Suppose you’re creating an application; in the application you need to create a method that can be called by
using a varying number of parameters. What should you use?
A) derived classes
B) interface
C) enumeration
D) method overloading

Answer 852

D) method overloading

Question 853

Suppose you’re creating an application that needs a delegate that can hold a reference of a method that can
return bool and accept an integer parameter. How would you define that delegate?
A) delegate bool myDelegate(int i, int j);
B) delegate bool (int i, int j);
C) delegate myDelegate(int i, int j);
D) delegate bool myDelegate(int i);

Answer 853

A) delegate bool myDelegate(int i, int j);

Question 854

Which property or method of task can be used as an alternative of the await keyword?
A) Result
B) Wait()
C) WaitAll()
D) Delay()

Answer 854

A) Result

Question 855

You’re creating an application that has many threads that run in parallel. You need to increment an integer
variable “i". How would you increment it in an atomic operation?
A)
 int i = 0;
 Interlocked.Increment(ref i);
B)
 int i = 0;
 Interlocked.Increment(i);

C)
 int i = 0;
 i++;
D)
 int i = 0;
 Interlocked.Increment(out i);

Answer 855

A)
int i = 0;
Interlocked.Increment(ref i);

Question 856

Suppose you’re creating a method that threw a new exception but it also threw an inner exception. See the
following code:
01. private void myMethod(int i)
02. {
03. try
04. {
05. ...
06. }
07. catch (ArgumentException ex)
08. {
09.
10. }
11. }
You must preserve the stack trace of the new exception and also throw the inner exception; which code
statement would you use in line 09?
A) throw ex;
B) throw new Exception("Unexpected Error", ex);
C) throw;
D) throw new Exception(ex)

Answer 856

B) throw new Exception(“Unexpected Error”, ex);

Question 857

Suppose you’re developing an application and you want to make a thread-safe code block for execution.
Which of the following code blocks would you use to write code?
A)
 object o = new object();
 lock (o)
 {
 ...
 }
B)
 object o = new object();
 lock (typeof(o))
 {
 ...
 }
Chapter 16 ■ Practice Exam Questions
429
C)
 lock (new object ())
 {
 ...
 }
D)
 lock
 {
 ...
 }

Answer 857

A)
 object o = new object();
 lock (o)
 {
 ...
 }

Question 858

Which of the following is the right syntax for using an asynchronous lambda expression?
A) Task task = async () => { … };
B) Task task = async () => { … };
C) Func task = async () => { … };
D) Action task = async (t) => { … };

Answer 858

C) Func task = async () => { … };

Question 859

When running a long-running asynchronous operation that returns a value, which keyword is used to wait
and get the result?
A) await
B) yield
C) return
D) async

Answer 859

A) await

Question 860

Which of the following collections is a thread-safe?
A) Dictionary
B) Stack
C) ConcurrentDictionary
D) Queue

Answer 860

C) ConcurrentDictionary

Question 861

Which keyword is useful for returning a single value from a method to the calling code?
A) yield
B) return
C) break
D) continue

Answer 861

A) yield

Question 862

Foreach loop can only run on:
A) anything
B) collection
C) const values
D) static values

Answer 862

B) collection

Question 863

In a switch statement, which keyword would you use to write a code when no case value satisfies?
A) else
B) default
C) return
D) yield

Answer 863

B) default

Question 864

How would you chain the execution of a task so that every next task runs when the previous task finishes its
execution? Which method you would use?
A) task.ContinueWith()
B) Task.Wait()
C) Task.Run()
D) Thread.Join()

Answer 864

A) task.ContinueWith()

Question 865

Which of the following methods is useful for holding the execution of a main thread until all background
tasks are executing?
A) Thread.Sleep()
B) Task.WaitAll()
C) Task.Wait()
D) Thread.Join()

Answer 865

B) Task.WaitAll()

Question 866

Which of following methods is accurate for holding the execution of a running task for a specific time?
A) Thread.Sleep()
B) Task.Delay()
C) Task.Wait()
D) Task.WaitAll()

Answer 866

B) Task.Delay()

Question 867

When handling an exception, which block is useful to release resources?
A) try
B) catch
C) finally
D) lock

Answer 867

C) finally

Question 868

Which keyword is used to prevent a class from inheriting?
A) sealed
B) lock
C) const
D) static

Answer 868

A) sealed

Question 869

await keyword can only be written with a method whose method signature has:
A) static keyword
B) async keyword
C) lock keyword
D) sealed keyword

Answer 869

B) async keyword

Question 870

Which of the following loops is faster?
A) for
B) do
C) Parallel.for
D) foreach

Answer 870

C) Parallel.for

Question 871

Which of the following keywords is useful for ignoring the remaining code execution and quickly jumping to
the next iteration of the loop?
A) break;
B) yield;
C) jump;
D) continue;

Answer 871

D) continue;

Question 872

You need to reference a method which returns a Boolean value and accepts two int parameters. Which of the
following delegates would you use?
A) Func func;
B) Action act;
C) Func func;
D) Action act;

Answer 872

A) Func func;

Question 873

You’re creating an application that contains the following code:
class Test
{
 public event Action Launched;
}
class Program
{
 static void Main(string[] args)
 {
 Test t = new Test();
 }
}
How would you subscribe a Launched event in the Main method to the “t” instance?
A) t.Launched += ()=>{..};
B) t.Launched = ()=>{..};
C) t.Launched -= ()=>{..};
D) t.Launched = t.Launched + ()=>{…};

Answer 873

A) t.Launched += ()=>{..};

Question 874

How do you throw an exception so the stack trace preserves the information?
A) throw;
B) throw new Exception();
C) throw ex;
D) return new Exception();

Answer 874

A) throw;

Question 875

To create a custom exception, which class is required to be inherited?
A) SystemException
B) System.Exception
C) System.Attribute
D) Enumerable

Answer 875

B) System.Exception

Question 876

An exception is handled on a method which mathematically calculates numbers. The method contains the
following catch blocks:
01.
02. catch(ArithmeticException e) { Console.WriteLine(“Arithmetic Error”); }
03.
04. catch (ArgumentException e) { Console.WriteLine(“Invalid Error”); }
05.
06. catch (Exception e) { Console.WriteLine(“General Error”); }
07.
You need to add the following code to the method:
catch (DivideByZeroException e) { Console.WriteLine(“Divide by Zero”); }
At which line should you insert the code?
A) 01
B) 03
C) 05
D) 07

Answer 876

A) 01

Question 877

A method name LongRunningMethod(CancellationTokenSource cts), takes a cancellation token source and
performs a long-running task. If the calling code requests cancellation, the method must Cancel the longrunning task and set the task status to TaskStatus.Canceled.
Which of the following methods should you use?
A) throw new AggregateException();
B) ct.ThrowIfCancellationRequested() ;
C) cts.Cancel();
D) if (ct.IsCancellationRequested) return;

Answer 877

B) ct.ThrowIfCancellationRequested() ;

Question 878

Which class should you preferably use for tracing in Release Mode?
A) Debug
B) Trace
C) TraceSource
D) All of the above

Answer 878

C) TraceSource

Question 879

To build a project you need a PDB file of:
A) Previous build version
B) Any build version
C) No need of PDB file
D) Same build version

Answer 879

D) Same build version

Question 880

Which method is the easiest way of finding the problem if you have no idea what it is?
A) Using Profiler
B) Profiling by Hand
C) Using Performance Counter
D) Debugging

Answer 880

A) Using Profiler

Question 881

Which of the following commands is required to create a strong name key?
A) sn -k {assembly_name}.snk
B) sn k {assembly_name}.snk
C) gacutil -i {assembly_name}.snk
D) gacutil i {assembly_name}.snk

Answer 881

A) sn -k {assembly_name}.snk

Question 882

Which of the following methods is used for getting the information of the current assembly?
A) Assembly. GetExecutingAssembly();
B) Assembly.GetExecutedAssembly();
C) Assembly.GetCurrentAssembly();
D) Assembly.ExecutingAssembly();

Answer 882

A) Assembly. GetExecutingAssembly();

Question 883

Which bindingflags are useful for getting the private data instance?
A) BindingFlags.NonPublic | BindingFlags.Instance
B) BindingFlags.Private | BindingFlags.Instance
C) BindingFlags.NonPrivate | BindingFlags.NonStatic
D) BindingFlags.Private | BindingFlags.NonStatic

Answer 883

A) BindingFlags.NonPublic | BindingFlags.Instance

Question 884

The application needs to encrypt highly sensitive data. Which algorithm should you use?
A) DES
B) Aes
C) TripleDES
D) RC2

Answer 884

B) Aes

Question 885

You are developing an application which transmits a large amount of data. You need to ensure the data
integrity. Which algorithm should you use?
A) RSA
B) HMACSHA256
C) Aes
D) RNGCryptoServiceProvider

Answer 885

B) HMACSHA256

Question 886

Salt Hashing is done by:
A) Merging data with random value and perform cryptography.
B) Merging data with random value and perform cryptanalysis.
C) Merging data with random value and perform encryption.
D) Merging data with random value and perform hashing

Answer 886

D) Merging data with random value and perform hashing

Question 887

You want to retrieve data from Microsoft Access 2013, which should be read-only. Which class you should use?
A) SqlDataAdapter
B) DbDataAdapter
C) OleDbDataReader
D) SqlDataReader

Answer 887

C) OleDbDataReader

Question 888

Suppose you created the ASMX Web Service named SampleService. Which class you would use to create the
proxy for this service?
A) SampleServiceSoapClient
B) SampleService
C) SampleServiceClient
D) SampleServiceSoapProxy

Answer 888

A) SampleServiceSoapClient

Question 889

Choose the correct code snippet/snippets for insert query (insert code snippet of C#, syntax vise):
A) SqlConnection con=new SqlConnection(“ConectionString”);
SqlCommand cmd=new SqlCommand(insertQuery,con);
Con.open();
Cmd.ExecuteNonQuery();
Con.close();
B) Using(SqlConnection con=new SqlConnection(“ConectionString”))
{
SqlCommand cmd=new SqlCommand(insertQuery,con);
Cmd.ExecuteNonQuery();
}
C) SqlConnection con=new SqlConnection(“ConectionString”);
Using( SqlCommand cmd=new SqlCommand(insertQuery,con))
{
Con.open();
Cmd.ExecuteNonQuery();
}
D) Using(SqlConnection con=new SqlConnection(“ConectionString”))
{
SqlCommand cmd=new SqlCommand(insertQuery,con);
Con.Open();
Cmd.ExecuteNonQuery();
}

Answer 889

A) SqlConnection con=new SqlConnection(“ConectionString”);
SqlCommand cmd=new SqlCommand(insertQuery,con);
Con.open();
Cmd.ExecuteNonQuery();
Con.close();

D) Using(SqlConnection con=new SqlConnection(“ConectionString”))
{
SqlCommand cmd=new SqlCommand(insertQuery,con);
Con.Open();
Cmd.ExecuteNonQuery();
}

Question 890

You are developing an application that retrieves Person type data from the Internet using JSON. You have
written the following function for receiving the data so far:
serializer.Deserialize(json);
Which code segment should you use before this function?
A) DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(Person));
B) DataContractSerializer serializer = new DataContractSerializer(typeof(Person));
C) JavaScriptSerializer serializer = new JavaScriptSerializer();
D) NetDataContractSerializer serializer = new NetDataContractSerializer();

Answer 890

C) JavaScriptSerializer serializer = new JavaScriptSerializer();

Question 891

Question 2
You need to store a large amount of data in a file. Which serializer would you consider better?
A) XmlSerializer
B) DataContractSerializer
C) DataContractJsonSerializer
D) BinaryFormatter
E) JavaScriptSerializer

Answer 891

D) BinaryFormatter

Question 892

You want to serialize data in Binary format but some members don’t need to be serialized. Which attribute
should you use?
A) XmlIgnore
B) NotSerialized
C) NonSerialized
D) Ignore

Answer 892

C) NonSerialized