Classes are the core of object-oriented languages such as Visual Basic or 4Test. Each GUI object is an instance of a class of objects. The class defines the actions, or methods, that can be performed on all objects of a given type. For example, in 4Test the PushButton class defines the methods that can be performed on all pushbuttons in your application. The methods defined for pushbuttons work only on pushbuttons, not on radio lists.
The class also defines the data, or properties, of an object. In 4Test and Visual Basic, you can set or retrieve the value of a property directly using the dot operator and a syntax similar to standard Visual Basic.