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Aetos2501
Asked: 2020-05-09 16:38:39 +0800 CST 2020-05-09 16:38:39 +0800 CST

What are "Handlers" in C#?

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Friends, I come across that word "Handlers" (manejador in Spanish). What are they used for or what relationship do they have with the delegates? If someone could guide me about what topics to read related to Handles or some examples, I would appreciate it.

c#

1 Answers

  1. Best Answer

    Handlers

    A "Handler" is an event handler method in the event receiver, that is, the one that is executed at the moment the receiver is notified that an event has occurred. For this, the method must be related to the event that it is going to control when it occurs.

    On the official page of the Microsoft MSDN site we have the following example:

    The following example shows a named event handler method  c_ThresholdReached that matches the signature of the EventHandler delegate. The method subscribes to the event  ThresholdReached.

    class Program
{
    static void Main(string[] args)
    {
        Counter c = new Counter();
        c.ThresholdReached += c_ThresholdReached;

        // provide remaining implementation for the class
    }

    static void c_ThresholdReached(object sender, EventArgs e)
    {
        Console.WriteLine("The threshold was reached.");
    }
}

    Delegates

    Delegates are simply variables that store a reference to a function that returns the same type of variable as the delegate, that is, they are variables that point to a function that returns the same type of variable.

    If your delegate is type void, it can only reference functions of type void.

    To declare a delegate you use the delegate keyword in (C#) and Delegate (in Visual Basic).

    On the official page of the Microsoft MSDN site we have the following example:

    The following example shows how to declare a delegate named  ThresholdReachedEventHandler:

    public delegate void ThresholdReachedEventHandler(object sender, ThresholdReachedEventArgs e);

    In this Stack Overflow answer in Spanish they answer more specifically about what are delegates in .net?

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