Declare a delegate and assigns a reference to either the WriteLine method or the ShowWindowsMessage method to its delegate instance. : delegate « delegate « C# / CSharp Tutorial

1. C# / CSharp Tutorial
2. delegate
3. delegate

using System;
using System.Windows.Forms;

delegate void DisplayMessage(string message);

public class TestCustomDelegate
{
   public static void Main()
   {
      DisplayMessage messageTarget; 

      if (Environment.GetCommandLineArgs().Length > 1)
         messageTarget = ShowWindowsMessage;
      else
         messageTarget = Console.WriteLine;

      messageTarget("Hello, World!");   
   }      

   private static void ShowWindowsMessage(string message)
   {
      MessageBox.Show(message);      
   }
}