... chapter 7 Advanced Types, Polymorphism, and Accessors I n Chapter 4, the basic notion of a reference type was presented. In this chapter, the more advanced, and certainly more important, ... implementation using internal types within a namespace. 129 130 Chapter 7: Advanced Types, Polymorphism, and Accessors ■ 7.1 Delegates and Events A delegate is a reference type to an instance or static ... saving. This time, the method Instance is “called back” 132 Chapter 7: Advanced Types, Polymorphism, and Accessors ■ within Out and returns a string that is used as part of the saving message. The...