Delegates

Abstract

A delegate is a user-defined type, like a class. But whereas a class represents a collection of data, a delegate keeps track of one or more methods. You use a delegate by doing the following. We’ll go through each of these steps in detail in the following sections.

• 1. Declare a new delegate type with a particular signature and return type. A delegate declaration looks like a method declaration, except that it doesn’t have an implementation block.

• 2. Declare a delegate variable of the new delegate type.

• 3. Create an object of the delegate type, and assign it to the delegate variable. The new delegate object includes a reference to a method with the same signature as defined in the first step.

• 4. Add additional methods into the delegate object. These methods must have the same signature and return type as the delegate type defined in the first step.

• 5. Throughout your code you can then invoke the delegate, just as it if it were a method. When you invoke the delegate, each of the methods it contains is executed.