Delegates in C#. An Overview

July 30, 2010 at 12:29 pm (Uncategorized)

A delegate is a type that refers to a static method or an instance method, and then used to call this method.

Following code explains how to create and use a delegate.

Steps involved are

1)Define the delegate type to specify its signature.
2)Declaring the Delegate Variable
3)Initializing the Delegate Variable with reference to any function
4)Calling the function

public class Program
 {
    //Defining the Delegate type
    public delegate double ProcessDelegate(int param1, int param2);

    public static double Multiply(int param1, int param2)
       {
            return param1 * param2;
       }

    public static double Divide(int param1, int param2)
       {
            return param1 / param2;
       }

    public static void Main(string[] args)
     {
        

public static void Main(string[] args)
{
  //Declaring the Delegate Variable
  ProcessDelegate processDelegate;

//Initializing Delegate Variable with reference to Multiply function
  processDelegate = new ProcessDelegate(Multiply);

  double result;
  result = processDelegate(6, 3);   // Calling the Delegate
  Console.WriteLine(result);

//Initializing the Delegate Variable with reference to Divide function            
  processDelegate = new ProcessDelegate(Divide);

  result = processDelegate(6, 3);   // Calling the Delegate
  Console.WriteLine(result);

  //Initializing the Delegate Variable with reference to Sum function
  Addition testClass = new Addition();
  processDelegate = new ProcessDelegate(testClass.Sum);

  result = processDelegate(6, 3);   // Calling the Delegate
  Console.WriteLine(result);

  Console.ReadKey();
 }

}

    public class Addition
    {
        public double Sum(int a, int b)
        {
            return a + b;
        }
    }

Note:- Signature of the delegate and function should match for a delegate to refer to a function