What is a Delegate?

Question

Please can anyone tell me the basic steps to create and use a delegate.

Answer 1

A Delegate is a reference to a function, in the same way that a TextBox variable is a reference to teh instance of a TextBox that appears on the screen.

They are surprisingly handy: you can use them to write code that can work to a variety of destinations without changing the code. For example, you could write a Print method that took a delegate:

private void DoPrint()
    {
    string text = "hello world!";
    Print(text, PrintConsole);
    Print(text, PrintTextbox);
    }
private void PrintConsole(string s)
    {
    Console.WriteLine("Console: " + s);
    }
private void PrintTextbox(string s)
    {
    myTextBox.Text = "TextBox: " + s;
    }
private delegate void printDestination(string s);
private void Print(string s, printDestination pd)
    {
    pd("From Print: " + s);
    }

You can completely change what happens to the text without changing the code in the Print method.

There are a lot of other uses, but that's the general idea.

Answer 2

=> A delegate is a type that represents references to methods with a particular parameter list and return type. When you instantiate a delegate, you can associate its instance with any method with a compatible signature and return type. You can invoke (or call) the method through the delegate instance.

=> EX. public delegate int PerformCalculation(int x, int y); use delegate keywork for create a delegate.