Delegates And Events - The Uncensored Story - Part 1

using System;

public delegate void ButtonEventHandler(object sender, ButtonEventArgs e);

public class ButtonEventArgs : EventArgs
{
	public string msg;
	
	public ButtonEventArgs(string message)
	{
		msg=message;
	}
}

class button
{
	private ButtonEventHandler beh=null; // For click
	  private ButtonEventHandler bep=null; // For press

	public void AddOnClick(ButtonEventHandler handler)
	{
		Console.WriteLine("Adding click event handler");
		beh=(ButtonEventHandler)Delegate.Combine(beh, handler);
	}
	
	public void RemoveOnClick(ButtonEventHandler handler)
	{
		Console.WriteLine("Removing click event handler");
		beh=(ButtonEventHandler)Delegate.Remove(beh, handler);
	}	
	
	protected virtual void OnClick(ButtonEventArgs e)
	{
		if (beh!=null)
		{
			beh(this, e);
		}
	}
	
	public void AddOnPress(ButtonEventHandler handler)
	{
		Console.WriteLine("Adding Press Event handler");
		bep=(ButtonEventHandler)Delegate.Combine(bep, handler);
	}
	
	public void RemoveOnPress(ButtonEventHandler handler)
	{
		Console.WriteLine("Removing Press Event handler");
		bep=(ButtonEventHandler)Delegate.Remove(bep, handler);
	}	
	
	protected virtual void OnPress(ButtonEventArgs e)
	{
		if (bep!=null)
		{
			bep(this, e);
		}
	}
	
	public void click()
	{
		ButtonEventArgs bea=new ButtonEventArgs("clicked");
		OnClick(bea);
	}
	
	public void press()
	{
		ButtonEventArgs bea=new ButtonEventArgs("pressed");
		OnPress(bea);
	}
}

public class DelegatesAndEvents
{
	private button button1=new button();
	private DelegatesAndEvents()
	{
		button1.AddOnClick(new ButtonEventHandler(ClickEventHandler1));
			button1.AddOnClick(new ButtonEventHandler(ClickEventHandler2));
			button1.AddOnClick(new ButtonEventHandler(ClickEventHandler3));
		
		button1.AddOnPress(new ButtonEventHandler(PressEventHandler));
 		button1.click();
		button1.press();
	}
	
	public static void Main(String [] args)
	{
		DelegatesAndEvents d=new DelegatesAndEvents();
	}
	
	public void ClickEventHandler1(object sender, ButtonEventArgs e)
	{
		Console.WriteLine("click event handler1");
		Console.WriteLine(e.msg);
		Console.WriteLine("after");
	}
	
	public void ClickEventHandler2(object sender, ButtonEventArgs e)
	{
		Console.WriteLine("click event handler2");
		Console.WriteLine(e.msg);
		Console.WriteLine("after");
	}

	public void ClickEventHandler3(object sender, ButtonEventArgs e)
	{
		Console.WriteLine("click event handler3");
		Console.WriteLine(e.msg);
		Console.WriteLine("after");
	}

	
	public void PressEventHandler(object sender, ButtonEventArgs e)
	{
		Console.WriteLine("press event handler");
		Console.WriteLine(e.msg);
		Console.WriteLine("after");
	}
}