How to use Delegates in C# to create a callbacks system.
- Authors
- Name
- Brent
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.