An event multicast demonstration : delegate event « delegate « C# / CSharp Tutorial

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

using System; 
 
delegate void MyEventHandler(); 
 
class MyEvent { 
  public event MyEventHandler SomeEvent; 
 
  public void OnSomeEvent() { 
    if(SomeEvent != null) 
      SomeEvent(); 
  } 
} 
 
class MouseEvent { 
  public void MouseEventHandler() { 
    Console.WriteLine("Event received by MouseEventHandler object"); 
  } 
} 
 
class KeyEvent { 
  public void KeyEventHandler() { 
    Console.WriteLine("Event received by KeyEventHandler object"); 
  } 
} 
 
class MainClass { 
  static void handler() { 
    Console.WriteLine("Event received by EventDemo"); 
  } 
 
  public static void Main() {  
    MyEvent evt = new MyEvent(); 
    MouseEvent xOb = new MouseEvent(); 
    KeyEvent yOb = new KeyEvent(); 
 
    evt.SomeEvent += handler; 
    evt.SomeEvent += xOb.MouseEventHandler; 
    evt.SomeEvent += yOb.KeyEventHandler; 
 
    evt.OnSomeEvent(); 
    Console.WriteLine(); 
 
    evt.SomeEvent -= xOb.MouseEventHandler; 
    evt.OnSomeEvent(); 
  } 
}

Event received by EventDemo
Event received by MouseEventHandler object
Event received by KeyEventHandler object

Event received by EventDemo
Event received by KeyEventHandler object