C# 4.0 Unleashed

Using .NET Events

Events are just delegates in disguise but provide additional levels of protection against the attacks we’ve seen previously. Syntactically, very little has to change:

See the difference? Instead of Tick and Finished being declared as properties with a delegate type, we now use the event keyword instead and drop the get and set property accessors. (You’ll see later how events have optional accessors called add and remove.)

At the use site, we can no longer write the following:

var countDown = new CountDown(5);// Hook up event handlerscountDown.Tick = currentSecond => Console.WriteLine(currentSecond);countDown.Finished = () => ...