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C# Delegates

In C#, a delegate is a type that represents a reference to a method. Delegates allow you to pass methods as arguments to other methods, store them as fields or variables, and invoke them. In this tutorial, we'll discuss how to define and use delegates in C#.

Syntax

The syntax for defining a delegate in C# is as follows:

delegate returnType delegateName(parameterList);

For example, here's how we can define a delegate for a method that takes two integers and returns their sum:

delegate int AddDelegate(int x, int y);

Now, we can use the delegate to reference the method:

int sum = addDelegate(5, 10);
Console.WriteLine(sum); // Output: 15

Example

Let's say we want to create a delegate called "StringDelegate" that returns a string and takes no arguments. Here's how we can implement it:

delegate string StringDelegate();

Now, we can use the delegate to reference a method that returns a string:

string GetHello() {
   return "Hello World!";
}

StringDelegate helloDelegate = new StringDelegate(GetHello);
string hello = helloDelegate();
Console.WriteLine(hello); // Output: Hello World!

Output

When we run the example code above, the output will be:

Hello World!

This is because we used the StringDelegate to reference the GetHello method and then invoked it to get the string "Hello World!", which we then printed to the console.

Explanation

In the example above, we defined a delegate called "StringDelegate" that returns a string and takes no arguments. We then defined a method called "GetHello" that returns the string "Hello World!". Finally, we created an instance of the delegate using the GetHello method and invoked it to get the string "Hello World!", which we then printed to the console.

Use

Delegates can be used in C# to pass methods as arguments to other methods, store them as fields or variables, and invoke them dynamically at runtime. This is useful when you want to write code that's more flexible and extensible, or when you want to provide a callback mechanism for asynchronous operations.

Important Points

  • Delegates can be used with any method with a compatible signature.
  • Delegates can be instantiated using a method name or an anonymous method.
  • Delegates can be combined or removed using the + and - operators, respectively.
  • Delegates can be used to provide callbacks for asynchronous operations, such as events.

Summary

In this tutorial, we discussed how to define and use delegates in C#. We covered the syntax, example, output, explanation, use, and important points of delegates in C#. With this knowledge, you can now use delegates in your C# code to pass methods as arguments, store them as fields or variables, or provide callback mechanisms for asynchronous operations.

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