//-- UserRequestEventArgs.cs

using System;

namespace EventSample
{
        
    public enum RequestType {AdRequest ,PersonalMessageRequest};
    
    /// <summary>
    /// Description of UserRequestEventArgs.
    /// </summary>
    public class UserRequestEventArgs:EventArgs
    {
        private RequestType request ;
        
        public UserRequestEventArgs(RequestType request)
            :base()
        {
            this.request = request;
        }
        
        public RequestType Request
        {
            get 
            {
                return request;
            }
        }
    }
}


//-- UserInputMonitor.cs

using System;

namespace EventSample
{        
    /// <summary>
    /// Description of UserInputMonitor.
    /// </summary>
    public class UserInputMonitor
    {
        
        public UserInputMonitor()
        {
            
        }
        
        public delegate void UserRequest(object sender, UserRequestEventArgs e);
        
        public event UserRequest OnUserRequest;
        
        public void Run()
        {
            while(true)
            {
                Console.WriteLine("select preferred option ");
                Console.WriteLine(" request advertisement - hit A then return " );
                Console.WriteLine(" request personal message from mortimer ---------" + 
                                  " hit P then return " );
                Console.WriteLine(" Exit - hit X then return " );
                
                string response  = Console.ReadLine();
                
                char responseChar = (response == "")?'-':char.ToUpper(response[0]);
                
                switch(responseChar)
                {
                    case 'A':
                        OnUserRequest(this,
                                      new UserRequestEventArgs(RequestType.AdRequest));
                        break;
                    case 'P':
                        OnUserRequest(this,
                                      new UserRequestEventArgs(RequestType.PersonalMessageRequest));
                        break;
                    case 'X':
                        return ;
                        
                }
                                        
            }
        }
    }
}


//--MessageDisplayer.cs
using System;

namespace EventSample
{
    /// <summary>
    /// Description of Class1.
    /// </summary>
    public class MessageDisplayer
    {
        public MessageDisplayer(UserInputMonitor monitor)
        {
            monitor.OnUserRequest +=
                new UserInputMonitor.UserRequest(UserRequestHandler);
        }
        
        protected void UserRequestHandler(object sender,UserRequestEventArgs e)
        {
            switch(e.Request)
            {
                case RequestType.AdRequest:
                    Console.WriteLine("Monitor Phone is better than anyone else" + 
                                     " because \n all our software is written in C#!\n");
                    break;
                case RequestType.PersonalMessageRequest:
                    Console.WriteLine("Today Monitor issued the following " + 
                                      "statement: \n Nevermore !\n ");
                    break;
                    
            }
        }
    }
}


//-- ManagersStaffMonitor.cs 
using System;
using System.Windows.Forms;
namespace EventSample
{
    /// <summary>
    /// Description of ManagersStaffMonitor.
    /// </summary>
    public class ManagersStaffMonitor
    {
        public ManagersStaffMonitor(UserInputMonitor monitor)            
        {
            monitor.OnUserRequest += 
                new UserInputMonitor.UserRequest(UserRequestHandler);            
        }
        
        protected void UserRequestHandler(object sender , UserRequestEventArgs e)
        {
            if(e.Request == RequestType.PersonalMessageRequest)
            {
                MessageBox.Show("Kaak!","Mortimer says ");
            }
        }
    }
}

//-- Main.cs
using System;
using System.Collections.Generic;
using System.Windows.Forms;

namespace EventSample
{
    class MainClass
    {
        public static void Main(string[] args)
        {
            UserInputMonitor inputMonitor = new UserInputMonitor();
            MessageDisplayer inputProcessor = new MessageDisplayer(inputMonitor);
            ManagersStaffMonitor mortimer = new ManagersStaffMonitor(inputMonitor);
            inputMonitor.Run();
        }
    }
}