Asp.Net core questions

Question 1

What is Asp.Net Core?

Answer 1

ASP.NET Core is a cross-platform, high-performance, open-source framework for building modern, cloud-enabled, Internet-connected apps. With ASP.NET Core, you can: Build web apps and services, Internet of Things (IoT) apps, and mobile backends.

-Abdul

Question 2

What is model binding in ASP.NET?

Answer 2

The model binding system fetches the data from multiple sources such as form fields, route data, and query strings. It also provides the data to controllers and views in method parameters and properties, converting plain string data to .NET objects and types in the process.

-Abdul

Question 3

What are the advantages of ASP.NET Core over ASP.NET?

Answer 3

There are the following advantages of ASP.NET Core over ASP.NET :

1 . It is cross-platform, so it can be run on Windows, Linux, and Mac.

2. There is no dependency on framework installation because all the required dependencies are shipped with our application
3. ASP.NET Core can handle more requests than the ASP.NET
4. Multiple deployment options available with ASP.NET Core

——– Madhu Vasanth

Question 4

What is middleware?

Answer 4

1. it is a pipeline that handles the http requests and http responses.
2. It is nothing but a component or class that can be executed for every request.
3. it contains httphandlers and httpmodules that are executed for every request.
4. there will be multiple middlewares . We can set the order of middleware execution.
5. Each middleware adds or modifies http request and passes control to the next middleware component.

———- Madhu Vasanth

Question 5

What is ASP.NET Controller?

Answer 5

1. it is the central unit of mvc application, it is first receipent which interacts with http request and sends it to respective models
   and gets the data and sends to respective view.
2. public methods in controller class are called as action methods.
3. it controls flow of application by taking input and rendering proper output.

————– Madhu Vasanth

Question 6

Differentiate between authentication and authorization.

Answer 6

1.Authentication is the process of verifying the identity of a user using some credentials like username and password while authorization determines the parts of the system to which a particular identity has access.
2.Authentication is required before authorization.

-Abdul

Question 7

Difference between ASP.NET and MVC?

Answer 7

• ASP.NET is a web application framework developed by Microsoft for building dynamic web pages, web applications, and web services. It provides a programming model, a set of libraries, and tools for building and deploying web applications.
• MVC (Model-View-Controller) is a design pattern used for developing web applications that separates the application into three components: the model, the view, and the controller.

1. Architecture: ASP.NET is a framework that supports multiple architectures, while MVC is a specific architecture pattern.
2. Separation of concerns: MVC separates the application into three components, whereas ASP.NET does not enforce any specific separation of concerns.

    - Manikandan R

Question 8

What is model binding in ASP.NET?

Answer 8

• Model binding is the process of mapping data in an HTTP request to properties or parameters of a model in an ASP.NET application. It allows you to automatically populate a model with data from the request without having to write manual code to extract the data from the request.
• In an ASP.NET application, model binding is performed by the default model binder. The default model binder uses the type and name of the model’s properties or parameters to map the values in the HTTP request to the corresponding properties or parameters of the model.

      - Manikandan R

Question 9

What is caching in ASP.NET and its types?

Answer 9

• Caching is the process of storing frequently accessed data in memory or on disk so that it can be retrieved more quickly when it is needed. In an ASP.NET application, caching can help to improve performance by reducing the amount of time it takes to retrieve data or generate content.
• ASP.NET provides several mechanisms for caching data,
  1. Output caching - Output caching stores the output of an entire page or user control in memory or on disk so that it can be quickly served to subsequent requests.
  2. Fragment caching - Fragment caching stores the output of a specific part of a page or user control in memory or on disk so that it can be quickly served to subsequent requests. NOT sure if its uspported
  3. Data caching - Data caching stores the results of a database query or other expensive operation in memory or on disk so that it can be quickly retrieved by subsequent requests.

    - Manikandan R

CORRECT ANSWER:https://learn.microsoft.com/en-us/aspnet/core/performance/caching/overview?view=aspnetcore-7.0

Question 10

what is action method?

Answer 10

“Action methods” refers to a specific type of method that is used in controllers in the MVC (Model-View-Controller) architecture.

Action methods are responsible for handling incoming HTTP requests and returning an appropriate response. They are called “action” methods because they typically perform some action, such as retrieving data from a database, updating data, or rendering a view.

An action method is a method in a controller class with the following restrictions:

It must be public.
Private or protected methods are not allowed.
It cannot be overloaded.
It cannot be a static method.
An action method executes an action in response to an HTTP request.

V.Mounika

Question 11

How is ASP.NET different from ASP.NET Core?

Answer 11

ASP.NET runs only on Windows, whereas ASP.NET Core can run on Windows, Linux, and macOS.

In ASP.NET Core, middleware is used to handle requests and responses, whereas in ASP.NET, server controls and events are used.

ASP.NET Core is more modular and lightweight than ASP.NET, which makes it easier and faster to develop web applications.

V.Mounika

Question 12

What are Action Return types?

Answer 12

ASP.NET Core provides the following options for web API controller action return types:

1.Specific type:

The action method can return primitive type like int, string or complex type like List etc.

2.IActionResult:

The IActionResult return type is appropriate when multiple ActionResult return types are possible in an action. The ActionResult types represent various HTTP status codes.

If there are multiple return types and paths in this type of action, liberal use of the [ProducesResponseType] attribute is necessary.This attribute produces more descriptive response details for web API.[ProducesResponseType] indicates the known types and HTTP status codes to be returned by the action.

3.ActionResult:

It enables returning a type deriving from ActionResult or return a specific type.
ActionResult<T> offers the following benefits over the IActionResult type:
->The [ProducesResponseType] attribute's Type property can be excluded.</T>

4.HttpResults:

The HttpResults can be useful when sharing code between Minimal APIs and Web API.

V.Mounika

Question 13

What is IIS?

Answer 13

IIS stands for Internet Information Services. It is a powerful web server developed by Microsoft. IIS can also act as a load balancer to distribute incoming HTTP requests to different application servers to allow high reliability and scalability.

• Ajithkumar

Question 14

What is Caching?

Answer 14

Caching is a technique of storing frequently used data/information in memory,
so that, when the same data/information is needed next time,
it could be directly retrieved from the memory instead of being generated by the application.
Caching is extremely important for performance boosting in ASP.NET
Types:
- Data caching
- Page caching
- Fragment caching

-Ajithkumar

Question 15

What is dependency injection?

Answer 15

Dependency injection is a design pattern that helps to develop loosely coupled code. This pattern is used extensively in ASP.NET.

Dependency injection means providing the objects that an object needs (its dependencies) in that object’s constructor instead of requiring the object to construct them.

Dependency injection reduces and often eliminates unnecessary dependencies between objects that don’t need to know each other. It also helps in testing by mocking or stubbing out the dependencies at runtime

-Ajithkumar

Question 16

what is routing ?

Answer 16

Routing in ASP.NET is the process of mapping incoming HTTP requests to a specific handler or controller action method. This allows you to create clean and friendly URLs for your web application, making it easier for users to navigate and for search engines to index.

-jyothish

Question 17

explain about filters?

Answer 17

Filters in ASP.NET are a way to intercept and modify the behavior of requests and responses in an ASP.NET MVC or Web API application. Filters are a powerful mechanism that can be used to implement cross-cutting concerns such as authentication, caching, logging, and error handling.

-jyothish

Question 18

what is CORS ?

Answer 18

CORS stands for Cross-Origin Resource Sharing. It is a security feature implemented by web browsers to prevent web pages from making requests to a different domain than the one that served the original page.

By default, web browsers enforce the same-origin policy, which means that a web page can only make requests to the same domain and protocol as the page itself. This policy is designed to prevent malicious scripts from accessing sensitive information from other domains.

-jyothish

Question 19

What is an Action Method?

Answer 19

An action method is a public method on a controller in ASP.NET MVC that is responsible for handling incoming HTTP requests and returning an HTTP response.

An action method can be used to perform a variety of tasks, such as querying a database, processing user input, and rendering a view.

An action method must be decorated with an attribute that specifies the HTTP method that it handles, such as [HttpGet] or [HttpPost].
-Maruthi

Question 20

Explain HTTP protocol.

Answer 20

HTTP protocol is a client-server protocol, Which works based on request sent and it responds with appropriate response.

The web browsers can be called as the client which sends the request to server, To be precise HTTP protocol helps in transmitting hypermedia documents

Mahesh

Question 21

Write down the name of all steps in the ASP.NET page life cycle?

Answer 21

Page request
Starting of page life cycle
Page initialization
Page Load
Validation
Post back event handling
Page rendering
Unload

by Raghu

Question 22

Write down features of ASP.NET?

Answer 22

Extending .NET Framework: ASP.NET is a subset of the .NET Framework as it extends the .NET Framework with some libraries and tools to develop web apps. The thing that it adds to the .NET Framework is Libraries for common web patterns like MVC, Editor Extensions, the base framework to process the web requests, and web-page templating syntax like Razor, etc.
Performance: It is faster than the other web frameworks available in the market.
Backend Code: With the help of ASP.NET you can write the backend code for data access and any logic in C#.
Dynamic Pages: In ASP.NET, Razor provides the syntax for developing dynamic web pages with the help of C# and HTML. ASP.NET can be integrated with JavaScript and it also includes the frameworks like React and Angular for the SPA(Single Page Application.)
Supporting different OS: You can develop and execute ASP.NET apps on Windows, Linux, Docker, and macOS. The Visual Studio provides the tools to build .NET apps with different OS.
-jyothish

Question 23

What is the web. config file?

Answer 23

A configuration file (web.config) is utilized to oversee different settings that characterize a website. The settings are store in XML files that are independent of your application code. In this manner, you can configure settings freely from your code. This file stored inside the application root directory.
by raghu

Question 24

What is the REST architecture?

Answer 24

REST stands for REpresentational State Transfer.REST is an architectural style that doesn’t follow any strict standard but follows six constraints defined by Roy Fielding in 2000. Those constraints are – Uniform Interface, Client-Server, Stateless, Cacheable, Layered System, Code on Demand.REST is not restricted to XML and it’s the choice of implementer which Media-Type to use like XML, JSON, Plain-text. Moreover, REST can use SOAP protocol but SOAP cannot use REST.REST is easy to implement and requires less bandwidth such as smartphones

by raghu

Question 25

what are Architectural Constraints of RESTful API?

Answer 25

There are six architectural constraints that make any web service are listed below:

Uniform Interface
Stateless
Cacheable
Client-Server
Layered System
Code on Demand

by raghu

Question 26

Explain the purpose of Web Services in ASP.NET?

Answer 26

Web services are components on a Web server that a client application can call by making HTTP requests across the Web. ASP.NET enables you to create custom Web services or to use built-in application services, and to call these services from any client application

by ajay

Question 27

What is Server control?

Answer 27

ASP.NET has Server Controls features, Which provide facilities to manipulated values of the controls on the Server-Side. This is especially helpful while we want to create validating and dynamically web forms.

by ajay

Question 28

What is Conventional Routing?

Answer 28

The conventional Routing sets a convention to the url. The controller name and action method names are used in the URL.

“{controller=Home}/{action=Index}/{id?}”)

first segment - Controller name, Second segment - action name

Mahesh

Question 29

what are http status codes in asp.net?

Answer 29

1xx - Informational Message
2xx - Successful
3xx - Redirection
4xx - Client Error
5xx - Server Error

by ajay

Question 30

What is attribute based routing?

Answer 30

This is an alternative strategy for routing, where the controller name and action name has no significance.

It is used in REST Api endpoint for webservices.

[Route(“Patient”)] this can be set to the controller

[HttpGet(“getall/patient”)] this can be set to the action method.

So the final url might be Patient/getall/patient

Mahesh

Question 31

What is the order of execution of the filters?

Answer 31

Filters run in the following order:

1.Authorization filters

2.Resource Filters

3.Action filters

4.Endpoint filters

5.Exception filters

6.Result filters

V.Mounika

Question 32

What is Action Filter all about? Any examples?

Answer 32

In ASP.NET Core, action filters are a type of filter that can be applied to an action method. Action filters allow developers to perform custom logic before or after an action method is executed. This can be useful for tasks such as logging, caching, and validation.

Action filters are defined using the ActionFilterAttribute class.
Here are some examples of how action filters might be used in ASP.NET Core:

Logging: An action filter can be used to log information about the request, such as the user’s IP address, the time the request was made, and the parameters that were passed to the action method. This can be useful for debugging and auditing purposes.
Caching: An action filter can be used to cache the result of an action method, so that subsequent requests for the same data can be served more quickly.
Authorization: An action filter can be used to enforce authorization rules for an action method, based on the user’s permissions or other contextual information.
Validation: An action filter can be used to perform validation on the parameters that are passed to an action method, to ensure that they are valid before the method is executed.

Question 33

What is Result filter all about?

Answer 33

In ASP.NET Core, result filters are a type of filter that can be applied to the result of an action method. Result filters allow developers to modify the result of an action method before it is returned to the client. This can be useful in a variety of scenarios, such as logging, caching, and error handling.

Result filters are defined using the ResultFilterAttribute class,
Result filters can be applied globally, at the controller level, or at the action method level.

Question 34

What is Authorization Filter?

Answer 34

Authorization filters are used to authenticate whether the user requested action method in the controller is authorized to access or not and for validating properties of the request. Authorization filters run before any other filter.

Question 35

What is content Negotiation all about?

Answer 35

Content negotiation is the process of selecting the best representation for a given response when there are multiple representations available. Means, depending on the Accept header value in the request, the server sends the response.

Question 36

What is the structure of HTTP Request?

Answer 36

The structure of an HTTP request message consists of several components:

1.Request line: This line specifies the HTTP method (e.g. GET, POST, PUT, DELETE, etc.) that the client wants to use, the URL of the resource, and the HTTP version (e.g. HTTP/1.1).

2.Headers: Headers provide additional information about the request, such as the user agent, the content type of the request body, the expected response format, authentication credentials, and caching instructions.
3.Message body (optional): The message body contains data that the client wants to send to the server, such as the contents of a form, a file to upload, or JSON data.

Question 37

What is the structure of HTTP Response?

Answer 37

The structure of an HTTP Response consists of the following elements:

Status Line: starts with the version number of HTTP, followed by a 3-digit status code and a reason phrase describing the status code. For example, HTTP/1.1 200 OK.

Headers: provide metadata about the response, including content type, content length, cache control, and more. Headers are separated from the body by a blank line.

Body: contains the actual response content, such as the HTML or JSON data requested by the client. The contents and length of the body depend on the specific request made and the server response.

Question 38

What is the use of Accept header?

Answer 38

The accept header is a property of the HTTP protocol that allows a server to provide specific content types from the same URL. The default values for the accept header when used in the various data source types works in most cases. In most cases, one of the formats is preferred even if no accept header is specified.

Question 39

What is the use of Content Header?

Answer 39

The content-type header indicates the type of media/file in communication between the HTTP client and the server. It helps the browser or server understand what format the information being sent/requested is in, improving the way it is processed and displayed.

Question 40

What is MVC design pattern all about?

Answer 40

he concerns of an application into three interconnected components: the model, the view, and the controller. This pattern is commonly used in web application development, including ASP.NET Core.

Model: The model represents the data and the business logic of the application. It defines the rules for data validation and interacts with the database or other storage mechanisms. In ASP.NET Core, the model can be a simple data structure or a complex object that includes additional methods and behaviors.

View: The view is responsible for presenting the data to the user in a user-friendly format. It is typically defined using HTML, CSS, and JavaScript and is responsible for rendering the user interface. In ASP.NET Core, views can be defined using Razor syntax, which allows for server-side code to be embedded directly into the HTML.

Controller: The controller is responsible for handling user requests, updating the model, and returning the appropriate view. It acts as an intermediary between the model and the view, processing user input and coordinating the flow of data between the two.

Question 41

What is a View? Explain its types?

Answer 41

In ASP.NET Core, a view is a user interface component that is responsible for rendering data to the user. Views are used to generate the HTML that is sent to the client’s web browser, and they are typically defined using a combination of HTML and server-side code.

There are two main types of views in ASP.NET Core:

Razor Views: Razor views are the most common type of view in ASP.NET Core. They are defined using a combination of HTML and Razor syntax, which allows server-side code to be embedded directly into the HTML.
Razor Pages: Razor Pages are a newer type of view in ASP.NET Core that allow developers to define UI and server-side logic in a single file. Unlike Razor views, which are typically divided into separate view and controller files, Razor Pages combine both the view and the controller into a single file.

Question 42

What is a Razor Syntax?

Answer 42

Razor syntax is a markup syntax used to create web pages using the ASP.NET framework. It is a mix of HTML markup and C# code, and it provides a simple, clean, and easy-to-read syntax for creating dynamic web content. Razor syntax can be used in ASP.NET MVC, ASP.NET Web Pages, and other web development frameworks. It allows developers to create web pages that are readable, maintainable, and easy to debug

Question 43

How do you manage state/session in Asp.Net?
Or How do you pass the data in Asp.Net between different components.

Answer 43

There are several ways to manage state/session in Asp.Net and pass data between different components:

Query String: You can pass data between pages or components by appending values to the URL using query strings.

Session State: You can store data in the session and use it across different pages or components. Session state is a server-side storage mechanism that stores user-specific data in a session.

Cookies: You can use cookies to store data on the client-side and access it across different pages or components.

Application State: You can store application-wide data in the Application object, which is accessible across all components in the application.

ViewState: ViewState is a client-side state management mechanism that stores the state of a page before the page posts back to the server.

TempData: TempData is a temporary data storage mechanism that is used to preserve data between two requests.

Cache: Cache is a mechanism that stores frequently accessed data in memory, so it can be accessed quickly without incurring a performance penalty.

Question 44

Explain the pipeline of Asp.Net core.

Answer 44

https://learn.microsoft.com/en-us/aspnet/core/fundamentals/middleware/?view=aspnetcore-6.0#middleware-order

Question 45

What is a Model and why is it used?

Answer 45

models are an important part of ASP.NET Core development because they provide a structured way to pass data between the view and the controller. By encapsulating data in a model, developers can ensure that the data being passed is valid and consistent, and that it conforms to a predefined schema.

Question 46

How do you do Validation in Asp.Net core?

Answer 46

In ASP.NET Core, there are several ways to perform validation, including client-side validation, server-side validation, and model binding validation. Here are some approaches for performing validation in ASP.NET Core:

Client-side validation: Client-side validation is performed in the user’s web browser using JavaScript. ASP.NET Core includes support for client-side validation through the use of jQuery Validation, which is a popular client-side validation library. By using the jquery.validate.unobtrusive.js script, ASP.NET Core can automatically generate client-side validation code based on server-side validation attributes. This approach can provide immediate feedback to the user without requiring a round-trip to the server.

Server-side validation: Server-side validation is performed on the server, after the data has been submitted by the user. In ASP.NET Core, server-side validation can be performed using the built-in validation attributes, such as [Required], [StringLength], and [RegularExpression]. These attributes can be added to model properties to enforce validation rules. To perform server-side validation, the ModelState dictionary can be used to store validation errors and display them to the user.

Model binding validation: Model binding validation is performed during the model binding process, which is responsible for mapping the HTTP request data to a model object.

Question 47

What are NuGet packages?

Answer 47

NuGet packages are collections of files, libraries, configuration settings, and other assets that are used to simplify the process of distributing and managing software in the .NET ecosystem. These packages can include a wide range of components, including code libraries, frameworks, drivers, tools, and plugins, and are designed to provide developers with a standardized way to share code and dependencies across different projects and platforms. NuGet is a package manager for the .NET platform and is widely used by .NET developers to manage their project dependencies and simplify development workflows

Question 48

What is the role of Startup class?

Answer 48

The Startup class is a C# class that’s responsible for configuring the application environment, including services and middleware, during app startup. It’s the first piece of code that gets executed when an application is launched. The Startup class is used in .NET Core and ASP.NET Core applications to perform the following tasks:

Define the application’s request handling pipeline by configuring middleware
Register services with the application’s dependency injection container
Configure the application’s settings
Add filters and options to the MVC framework
Set up logging, database connections, and other services required for the application to run

Question 49

What is the role of ConfigureServices and Configure method?

Answer 49

In ASP.NET Core, the ConfigureServices and Configure methods are important methods in the startup class that are responsible for configuring the application services and the HTTP request pipeline, respectively.

ConfigureServices: This method is called first when the application starts up, and its purpose is to configure the services that the application needs. This method is used to register services with the dependency injection container, which can then be used by other parts of the application. Services can include things like database contexts, repositories, logging, and other application-specific services.

Configure: This method is called after the ConfigureServices method, and its purpose is to configure the HTTP request pipeline for the application. This method is used to add middleware components to the pipeline that handle incoming HTTP requests and outgoing HTTP responses. Middleware components can include things like authentication, routing, error handling, caching, and other application-specific middleware.

Question 50

Describe the Dependency Injection.

Answer 50

Dependency injection is a design pattern that allows objects to be loosely coupled by having their external dependencies injected into them rather than creating those dependencies internally. This means that the objects do not have to know the intricacies of creating their dependencies, but rather, the dependencies are supplied to them externally, making the system more flexible and less tightly coupled. Dependency injection enables better separation of concerns, enhances testability, and improves maintainability of code.

Question 51

What problems does Dependency Injection solve?

Answer 51

Tight Coupling: Tight coupling occurs when one class depends on another class, and any changes to the dependent class can cause changes in the class that is using it. DI helps in reducing tight coupling by decoupling classes, which means the dependent class is no longer directly dependent on the class that is using it.

Testability: Testing is an important aspect of software development, and it is difficult to test a class that depends on other classes. DI helps in testing the code in isolation by allowing developers to inject mock objects instead of real objects during testing.

Scalability: DI makes it easier to scale up the application by allowing developers to change the dependencies of a class without changing the code. This makes it possible to swap out dependencies with new implementations or services.

Maintainability: As the application grows in complexity, it becomes difficult to manage dependencies between classes. DI helps in reducing the complexity of the application by centralizing the configuration of dependencies and making it easier to maintain.

Reusability: DI makes it possible to reuse code across multiple applications by making it easier to separate the dependencies of a class from the class itself. This makes it possible to use the same class in different contexts without changing the code.

Overall, Dependency Injection helps to promote better code quality, testability, maintainability, and scalability in software applications.

Question 52

Describe the Service Lifetimes in Asp.Net core

Answer 52

In ASP.NET Core, service lifetimes determine how long a service should be kept in memory and how many instances of that service should be created. ASP.NET Core supports three main service lifetimes:

Transient: A new instance of the service is created each time it’s requested. This is useful for lightweight and stateless services.

Scoped: A new instance of the service is created once per client request or scope. This is useful for services that require some state to be maintained during the handling of a single client request.

Singleton: Only one instance of the service is created for the lifetime of the application. This is useful for services that are expensive to create or need to maintain state across multiple requests.

Question 53

Describe the Servers in ASP.NET Core.

Answer 53

ASP.NET Core supports multiple server options to host and run your web applications.
Kestrel Server: Kestrel is the default and recommended server for ASP.NET Core. It’s a cross-platform, lightweight, and fast server that can handle thousands of connections concurrently.
HTTP.sys Server: HTTP.sys is a Windows-only server that is optimized for handling requests on Windows operating systems.
IIS Server: You can also host your ASP.NET Core application on IIS by using the ASP.NET Core Module.
Nginx Server: Nginx is a popular open-source reverse proxy server that can be used to host ASP.NET Core applications.

Question 54

How Logging works in .NET Core and ASP.NET Core?

Answer 54

Logging is an important feature of any application, and .NET Core and ASP.NET Core provide a powerful and flexible logging framework that makes it easy to log application events and errors.

The logging framework in .NET Core and ASP.NET Core is based on the ILogger interface, which defines a set of methods for logging different types of messages, including debug, information, warning, and error messages. To use the logging framework in your application, you need to create an instance of the ILogger interface and call the appropriate logging method based on the severity of the message.

Question 55

How Routing works in ASP.NET Core?

Answer 55

Routing in ASP.NET Core is the process of mapping incoming requests to the appropriate controller action method. ASP.NET Core routing works by using the Routing Middleware, which is responsible for matching incoming URLs to registered routes. Routing Middleware takes a URL and tries to find a matching route in the RouteCollection.