Stephens' C# Programming with Visual Studio® 2010 24-Hour Trainer

Defining Classes

This book hasn’t emphasized the fact, but you’ve been working with classes since the very

beginning. The very first program you created in Lesson 1 included several classes such as

the program’s main form and some behind-the-scenes classes that help get the program run-

ning. Since then, you’ve used all kinds of control classes, the

MessageBox class, the Array

class, collection classes, and more. You can even treat primitive data types such as

int and

string as classes under some circumstances.

In this lesson you learn how to create your own classes. You learn how to define a class and

give it properties, methods, and events to make it useful.

WHAT IS A CLASS?

A class defines a type of object. It defines the properties, methods, and events provided by its

type of object. After you define a class, you can make as many instances of that class as you like.

For example, the

Button class defines the properties and behaviors of a button user interface

element. You can create any number of instances of

Buttons and place them on your forms.

You can think of a class as a blueprint for making objects. When you create an instance

of the class, you use the blueprint to make an object that has the properties and behaviors

defined by the class.

You can also think of a class as a cookie cutter. Once you’ve created the cookie cutter, you can

make any number of cookies that all have the same ...