Use the built-in EventHandler delegate : event « GUI Windows Forms « C# / CSharp Tutorial

1. C# / CSharp Tutorial
2. GUI Windows Forms
3. event

using System; 
 
// Declare an event class. 
class MyEvent { 
  public event EventHandler SomeEvent; // uses EventHandler delegate 
 
  // This is called to fire SomeEvent. 
  public void OnSomeEvent() { 
    if(SomeEvent != null) 
      SomeEvent(this, EventArgs.Empty); 
  } 
} 
 
class MainClass { 
  static void handler(object source, EventArgs arg) { 
    Console.WriteLine("Event occurred"); 
    Console.WriteLine("Source is " + source); 
  } 
 
  public static void Main() {  
    MyEvent evt = new MyEvent(); 
 
    // Add handler() to the event list. 
    evt.SomeEvent += handler; 
 
    // Fire the event. 
    evt.OnSomeEvent(); 
  } 
}

Event occurred
Source is MyEvent