Programming Visual Basic 2008

Chapter 12. Overloads and Extensions

Do you ever wish you could do things beyond what people were designed to do? Like flying? We all dream about it, but we can’t do it without several hundred pounds of jet fuel. Or what about bending steel in our bare hands? Does that sound like anyone you know? Then there’s breathing underwater, doing long division in your head, speaking a foreign language fluently without much study, and having a successful career as an author of popular computer books. Ah, one can dream.

It’s not that we want to do all of these things, but once in a while it would be nice to be slightly enhanced with the ability to do one or two of the things that are beyond our natural abilities. Unfortunately, it doesn’t work for humans very often, but could it work for .NET operators?

You probably didn’t even know that the humble Visual Basic addition operator (+) had dreams of flying, or of speaking Hungarian, or of bending steel. Well, operators are people, too. And now their dreams can be fulfilled because Visual Basic supports operator overloading.

This chapter will show how you can direct the body-building enhancement process for the various Visual Basic operators. I’ll also introduce extension methods, which let you similarly enhance classes, even if you don’t have access to the original source code for those classes.

What Is Operator Overloading?

Operator overloading allows your code to enhance the basic Visual Basic operators, and endow them with abilities not previously ...