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  

427

PART IPART I

    // Can't store this one -- full.

    evt.SomeEvent += zOb.Zhandler;

    Console.WriteLine();

    // Fire the events.

    evt.OnSomeEvent();

    Console.WriteLine();

    // Remove a handler.

    Console.WriteLine("Remove xOb.Xhandler.");

    evt.SomeEvent -= xOb.Xhandler;

    evt.OnSomeEvent();

    Console.WriteLine();

    // Try to remove it again.

    Console.WriteLine("Try to remove xOb.Xhandler again.");

    evt.SomeEvent -= xOb.Xhandler;

    evt.OnSomeEvent();

    Console.WriteLine();

    // Now, add Zhandler.

    Console.WriteLine("Add zOb.Zhandler.");

    evt.SomeEvent += zOb.Zhandler;

    evt.OnSomeEvent();

  }

}

The output from the program is shown here:

Adding events.

Event list full.

Event received by W object

Event received by X object

Event received by Y object

Remove xOb.Xhandler.

Event received by W object

Event received by Y object

Try to remove xOb.Xhandler again.

Event handler not found.

Event received by W object

Event received by Y object

Add zOb.Zhandler.

Event received by W object

Event received by Z object

Event received by Y object

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P a r t   I :  

T h e   C #   L a n g u a g e

Let’s examine this program closely. First, an event handler delegate called