|       | delegates/4/Messenger.cs - Install and UnInstall message methods in the Messenger class. | Lecture 5 - slide 35 : 45 Program 1 | 
using System;
public delegate void Message(string txt);  
public class Messenger{
  
  private string sender;
  private Message message;  
  public Messenger(string sender){  
   this.sender = sender;
   message = null;
  }
  public Messenger(string sender, Message aMessage){  
   this.sender = sender;
   message = aMessage;
  }
  public void InstallMessage(Message mes){  
   this.message += mes;                     
  }   
  public void UnInstallMessage(Message mes){  
   this.message -= mes;                       
  }   
  public void DoSend(){                       
   message("Message from " + sender);         
  }
}