C# 5.0 ALL-IN-ONE FOR DUMMIES by Bill Sempf Chuck Sphar & Stephen Randy Davis

Author:Bill Sempf, Chuck Sphar & Stephen Randy Davis
Language: eng
Format: epub
Publisher: John Wiley and Sons, Inc.
Published: 2013-01-13T16:00:00+00:00

Figure 9-1: Making progress with the Windows ProgressBar control.

Defining a Delegate

C# provides delegates for making callbacks — and a number of other tasks. Delegates are the C# way (the .NET way, really, because any .NET language can use them) for you to pass around methods as though they were data.

You’re saying, “Here, execute this method when you need it” (and then handing over the method to execute).

This chapter helps you get a handle on that concept, see its usefulness, and start using it yourself.

You may be an experienced coder who will recognize immediately that delegates are similar to C/C++ function pointers — only much, much better. But I’m assuming in this section that you aren’t and you don’t.

Think of a delegate as a vehicle for passing a callback method to a “workhorse” method that needs to call you back or needs help with that action, as in doing the same action to each element of a collection. Because the collection doesn’t know about your custom action, you need a way to provide the action for the collection to carry out. Figure 9-2 shows how the parts of this scheme fit together.

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