Web Services: Building Reusable Web Components with SOAP and ASP.NET(English)

The rest of the page contains the code that implements the class. I first use the Imports directive, a new feature of Visual Basic.NET, which tells the compiler to import the namespaces. The term "namespace" is a fancy way to refer to the description of a set of prefabricated functionality. It is conceptually identical to a reference in your Visual Basic 6.0 project. Since ASP.NET will compile this example@#s code "just-in-time" when a request arrives from a client, I don@#t have a project in which to set these references, so I have to explicitly add them to the code. The names following Imports tell the compiler which sets of functionality to include the references for. In this case, System and System.Web.Services contain the prefabricated features you need to write a Web Service.

The next line defines the name of the class. This class in Visual Basic is similar to many you@#ve written. You@#ll see a brand new keyword (Inherits) at the end of the line: Inherits WebService. This represents one of the main enhancements in Visual Basic.NET—support for the object-oriented concept called inheritance. When you say that your new TimeService class inherits from the WebService class, you are telling the compiler to take all the code from the system-provided class named WebService (known as the base class) and include it in your new TimeService class (known as the derived class). And in addition to reusing the code from the class you inherit from, you can add, alter, and override the functionalities of that class in your new clan. Think of inheritance as cutting and pasting without actually moving anything. In fact, seriously deranged C++ and Java-language geeks often refer to physically cutting and pasting code as editor inheritance.