This chapter is from the book
This chapter is from the book
This chapter is from the book
Summary
As you read through this chapter, one theme probably became clear: The use of inheritance increases your responsibilities both during the design phase and during the coding phase. If you decide to create a class from which other classes will inherit, you must make several extra design decisions. If you make these decisions incorrectly, you can get yourself into hot water pretty quickly. This is especially true when you need to revise a base class after other programmers have already begun to use it.
The first question you should address is whether it makes sense to use inheritance in your designs. In other words, should you be designing and writing your own base classes to be inherited by other classes? Once you've made a decision to use inheritance in this manner, you take on all the responsibilities of a base class author. It's your job to make sure that every derived class author understands the programming contract your base class has defined for its derived classes.
While you may never create your own base class, you will more than likely create custom classes that inherit from someone else's base class. It's difficult to imagine that you could program against the classes of the FCL without being required to inherit from a system-provided base class such as the Form class, the Page class, or the WebService class. Because so many of the class libraries in the .NET Framework have designs that involve base classes, every .NET developer needs to understand the responsibilities of a derived class author. If you don't have a solid understanding of the issues at hand, you will find it difficult to implement a derived class correctly.