JScript .NET, Part IV: Inheritance

In this column we continue our series on JScript .NET. In Part I, we laid down the groundwork for JScript .NET, showing you how to install IIS and the .NET SDK, and how to compile and run a JScript .NET program. In Part II, we showed you the major differences between JavaScript and JScript .NET. In Part III, we focused on JScript .NET's classes and their division among namespaces. In this column, we further develop the inheritence concepts of JScript .NET.

Inheritance is one of the key capabilities of object oriented programming languages. In this column we will show you different aspects of how JScript .NET supports inheritence. We will show you how to extend base classes into derived classes. We'll introduce the concept of interfaces, and why they are so important for keeping the system architecture clean. We'll explain the difference between extending a class and implementing an interface. We'll show you several modifiers that you can use to change the default behavior of classes and derived classes: abstract, final, override, and hide.

In this column you will learn:

• How to extend a base class
• How to write an interface
• How to define abstract classes
• How to override base class methods
• How to avoid overriding base classes