How to use Delegates in C# to create a callbacks system.

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Using Delegates in C#: A Practical Example

Delegates are a powerful feature in C# that allow you to pass a method as a parameter to another method.

This can be particularly useful when working with callbacks, where you need to execute a certain method after an event has occurred.

In this blog post, we'll take a look at how to use delegates in C# to create a callback system.

First, let's define a delegate type that we'll use as our callback.

A delegate type is defined like this:

public delegate void MyCallback();

In this example, the delegate type is called MyCallback, and it takes no parameters and returns no value (void).

Now we can use this delegate type in a method that takes a MyCallback parameter and calls it when an event occurs.

Here's an example of a method that simulates a long-running operation and calls a callback when it's done:

public static void DoWork(MyCallback callback)
{
    for (int i = 0; i < 100; i++)
    {
        // Simulate some work
        System.Threading.Thread.Sleep(100);
    }
    callback();
}

Now we can call the DoWork method and pass it a method to be called as a callback:

public static void WorkDone()
{
    Console.WriteLine("Work is done!");
}

DoWork(WorkDone);

Here we are passing the WorkDone method as a parameter to the DoWork method, so that it will be called once the work is done.

Another way to pass a callback to a method is by using anonymous methods, like this:

DoWork(delegate { Console.WriteLine("Work is done!"); });

or by using lambda expression

DoWork(() => { Console.WriteLine("Work is done!"); });

In this example, we're passing an anonymous method that writes "Work is done!" to the console as a parameter to the DoWork method.

Summary

In conclusion, delegates in C# provide a powerful mechanism for creating callback systems.

By defining a delegate type and using it as a parameter in a method, you can pass any method that matches the delegate's signature as a callback.

This allows you to separate the logic of the long-running operation from the logic that should be executed after the operation is complete, making your code more modular and easy to understand.

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