C# 0 The Complete Reference

PART I

C h a p t e r   1 5 :  

D e l e g a t e s ,   E v e n t s ,   a n d   L a m b d a   E x p r e s s i o n s  

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PART IPART I

  static void Main() {

    MyEvent evt = new MyEvent();

    // Add Handler() to the event list.

    evt.SomeEvent += Handler;

    // Fire the event.

    evt.OnSomeEvent();

  }

}

In this case, the 

EventArgs

 parameter is unused and is passed the placeholder object 

EventArgs.Empty

. The output is shown here:

Event occurred

Source is MyEvent

Applying Events: A Case Study

Events are frequently used in message-based environments such as Windows. In such an 

environment, a program simply waits until it receives a message, and then it takes the 

appropriate action. Such an architecture is well suited for C#-style event handling because it 

is possible to create event handlers for various messages and then simply invoke a handler 

when a message is received. For example, the left-button mouse click message could be tied 

to an event called 

LButtonClick

. When a left-button click is received, a method called