What is a Delegate?

       
          Delegate is a type which  holds the method(s) reference in an object. It is also referred to as a type safe function pointer.

Advantages

• Encapsulating the method's call from caller
• Effective use of delegate improves the performance of application
• Used to call a method asynchronously

Declaration

public delegate type_of_delegate delegate_name()

Example:

public delegate double Delegate_Prod(int a,int b);

class Class1

{

    static double fn_Prodvalues(int val1,int val2)

    {

        return val1*val2;

    }

    static void Main(string[] args)

    {

        //Creating the Delegate Instance

        Delegate_Prod delObj = new Delegate_Prod(fn_Prodvalues);

        Console.Write("Please Enter Values");

        int v1 = Int32.Parse(Console.ReadLine());

        int v2 = Int32.Parse(Console.ReadLine());

        //use a delegate for processing

        double res = delObj(v1,v2);

        Console.WriteLine ("Result :"+res);

        Console.ReadLine();

    }

}

Explanation         

·         Here I have used a small program which demonstrates the use of delegate.

·         The delegate "Delegate_Prod" is declared with double return type and accepts only two integer parameters.

·         Inside the class, the method named fn_Prodvalues is defined with double return type and two integer parameters. (The delegate and method have the same signature and parameter type.)