SD

Question 1

What is a delegate in C#?

Answer 1

A delegate is a type that represents references to methods with a specific parameter list and return type.

Question 2

How can you declare a delegate in C#?

Answer 2

You can declare a delegate using the delegate keyword followed by the return type and parameters of the method it will reference.

Question 3

Can a delegate reference static methods?

Answer 3

Yes, a delegate can reference both instance methods and static methods.

Question 4

What is a multicast delegate in C#?

Answer 4

A multicast delegate is a delegate that holds references to multiple methods.

Question 5

How can you add methods to a multicast delegate in C#?

Answer 5

You can add methods to a multicast delegate using the += operator.

Question 6

What is the purpose of the Invoke method in C# delegates?

Answer 6

The Invoke method is used to call the methods that the delegate references.

Question 7

What is the difference between delegates and interfaces in C#?

Answer 7

Delegates are similar to interfaces but are used to create references to methods rather than defining a contract for classes.

Question 8

Can delegates be used for event handling in C#?

Answer 8

Yes, delegates are commonly used for event handling in C#.

Question 9

What is a callback in C#?

Answer 9

A callback is a method that is passed as an argument to another method and is called when a certain event occurs.

Question 10

How can you define a delegate with a custom signature in C#?

Answer 10

You can define a delegate with a custom signature by specifying the return type and parameters that the delegate will reference.

Question 11

Can delegates be used for asynchronous programming in C#?

Answer 11

Yes, delegates can be used for asynchronous programming in C# by using the BeginInvoke and EndInvoke methods.

Question 12

What is covariance in relation to delegates in C#?

Answer 12

Covariance allows you to assign a method that returns a more derived type to a delegate that returns a less derived type.

Question 13

What is contravariance in relation to delegates in C#?

Answer 13

Contravariance allows you to assign a method that accepts a less derived type as a parameter to a delegate that expects a more derived type.

Question 14

How can you check if a delegate is null in C#?

Answer 14

You can check if a delegate is null by comparing it to null or using the Equality operator.

Question 15

What is the difference between synchronous and asynchronous delegates in C#?

Answer 15

Synchronous delegates execute the methods immediately, while asynchronous delegates allow the methods to execute on a separate thread.

Question 16

How can you remove a method from a multicast delegate in C#?

Answer 16

You can remove a method from a multicast delegate using the -= operator.

Question 17

What is the purpose of the GetInvocationList method in C# delegates?

Answer 17

The GetInvocationList method returns an array of delegates that represent the methods currently referenced by a multicast delegate.

Question 18

Can delegates be used with lambda expressions in C#?

Answer 18

Yes, delegates can be used with lambda expressions to create inline methods.

Question 19

What is the difference between a delegate and an event in C#?

Answer 19

An event is a special type of delegate that can only be invoked from within the class that defines it.

Question 20

How can you create a generic delegate in C#?

Answer 20

You can create a generic delegate by using the generic type parameters when declaring the delegate.

Question 21

What is the purpose of the DynamicInvoke method in C# delegates?

Answer 21

The DynamicInvoke method is used to invoke the methods that the delegate references with parameters passed as an object array.

Question 22

Can delegates be used with anonymous methods in C#?

Answer 22

Yes, delegates can be used with anonymous methods to define inline methods without a separate method declaration.

Question 23

What is the difference between a delegate and a function pointer?

Answer 23

Function pointers are a feature of C and C++, while delegates are a type-safe object-oriented way to refer to methods in C#.

Question 24

How can you pass a delegate as a parameter in C#?

Answer 24

You can pass a delegate as a parameter by declaring the parameter as the delegate type that the method expects.