Programming .NET Windows Applications

Forms Inheritance

One of the .NET Framework's powerful features is that it is fully object-oriented, which, among other things, allows class inheritance. Inheritance promotes reuse of objects, potentially saving the developer (and his employer) from a great deal of work. Reusing tested and working code reduces development time and cuts down on the number of bugs.

With inheritance, a class can derive (inherit) from a base class. The derived class is a specialized case of the base class. For example, if you were modeling the animal kingdom, your Dog class might derive from Mammal, indicating that a Dog is a specialized type of Mammal.

All forms in Windows Forms are members of the Form class. As such, they derive from the System.Windows.Forms class. Any form you create can also be the base class for other forms derived from it. A derived form will have all the properties, controls, and code contained by the base form, plus any additional properties, controls, and code of its own.

This organization provides a powerful way to impose a consistent look and feel across multiple forms. Any changes made in a base form will automatically propagate to all its derived forms when the application is recompiled. In addition, the derived form can override properties and methods. This will be demonstrated in the examples below.

Inheritance also allows controls with common functionality to be placed in a base form and be available to any derived form. By overriding methods in the derived form, the same ...