Như bạn thấy, Editor sẽ mở ra một tooltip hướng dẫn bạn đến TAB loại để tạo ra một trường hợp đại biểu mới. Loại TAB và Mã hoàn thành sẽ xuất hiện một tooltip cho việc tạo ra các phương pháp xử lý, như trong Hình 4-2. Trong Hình 4-2, bạn có thể thấy rằng luật hoàn thành là đề xuất một tên phương pháp cho bạn. Bạn có thể lựa chọn cách nhấn TAB hoặc thay đổi tên phương thức và sau đó nhấn TAB. . | 96 Microsoft Visual Studio 2010 A Beginner s Guide Figure 4-2 Code completion for handler method creation As you can see the Editor pops up a tooltip instructing you to type tab to create a new delegate instance. Type tab and Code Completion will pop up another tooltip for creating the handler method as shown in Figure 4-2. In Figure 4-2 you can see that Code Completion is suggesting a method name for you. You have a choice of pressing tab or changing the method name and then pressing tab. Either way you have a fast way to hook up a handler method to an event via the event s delegate type. Just as a delegate provides an interface to a method that is a contract basically to describe how to communicate you can also define interfaces to classes to communicate with them in a specified way and these are intuitively named . . . interfaces. Implementing Interfaces Another language feature that gives you flexibility is interfaces. An interface can be useful if you want to have a group of classes that can be interchanged at any time yet you need to write the same operations for each of these classes. Essentially you want to write the code that uses the class only one time but still switch what the actual class is. That s where interfaces come in. The interface creates a contract that each of the interchangeable classes must adhere to. So if the interface says that all classes that implement the interface have method A and property B then every class that implements the interface must have method A and property B the compiler enforces this like a contract that cannot be broken. The following sections show you how to write an interface and then build a couple of classes that implement that interface. Finally you ll see how to write code against the interface. One important fact to remember about interfaces is that they don t have any code other than definitions of members. This definition of members is the contract of the interface. You are the one who must to write a class .
