{filelink=15055}

class="codeShade">
/*
C#: The Complete Reference
by Herbert Schildt 

Publisher: Osborne/McGraw-Hill (March 8, 2002)
ISBN: 0072134852
*/

// A .NET-compatible event. 

using System; 

// Derive a class from EventArgs.
class MyEventArgs : EventArgs {
  public int eventnum;
} 

// Declare a delegate for an event.
delegate void MyEventHandler(object source, MyEventArgs arg); 

// Declare an event class.
class MyEvent {
  static int count = 0; 

  public event MyEventHandler SomeEvent; 

  // This fires SomeEvent.
  public void OnSomeEvent() {
    MyEventArgs arg = new MyEventArgs(); 

    if(SomeEvent != null) {
      arg.eventnum = count++;
      SomeEvent(this, arg);
    }
  }
} 

class X {
  public void handler(object source, MyEventArgs arg) {
    Console.WriteLine("Event " + arg.eventnum +
                      " received by an X object.");
    Console.WriteLine("Source is " + source);
    Console.WriteLine();
  }
} 

class Y {
  public void handler(object source, MyEventArgs arg) {
    Console.WriteLine("Event " + arg.eventnum +
                      " received by a Y object.");
    Console.WriteLine("Source is " + source);
    Console.WriteLine();
  }
} 

public class EventDemo5 {
  public static void Main() {
    X ob1 = new X();
    Y ob2 = new Y();
    MyEvent evt = new MyEvent(); 

    // Add handler() to the event list.
    evt.SomeEvent += new MyEventHandler(ob1.handler);
    evt.SomeEvent += new MyEventHandler(ob2.handler); 

    // Fire the event.
    evt.OnSomeEvent();
    evt.OnSomeEvent();
  }
}