Essential C# 3.0: For .NET Framework 3.5

13. Events

IN THE PRECEDING CHAPTER, you saw how to store a single method inside an instance of a delegate type and invoke that method via the delegate. Delegates comprise the building blocks of a larger pattern called publish-subscribe. The use of delegates and their support for publish-subscribe patterns is the focus of this chapter. Virtually everything described within this chapter is possible to do using delegates alone. However, the event constructs that this chapter focuses on provide important encapsulation, making the publish-and-subscribe pattern easier to implement and less error-prone.

In the preceding chapter, all delegates were for a single callback (a multiplicity of one). However, a single delegate variable can reference a series ...