Every Object Has A Type
Each object is an instance of a class, where 'class'
is synonymous with 'type'. Object oriented terms use
the word class to refer to the properties, events,
and methods that uniquely define a type of object.
A class contains the information that is needed
to create an object of that class. |
The form and controls you use to build a program
are actually instances of their respective classes.
The most important distinguishing characteristic of
a class is "what messages can you send to it?"
Objects Have Life Cycles
To be used, objects must be created. At some point,
when they are not needed any more, they should be
destroyed because they use resources. When an object
is destroyed, the memory that was being used by that
object is freed and is then available for reuse.
|
|
In this chapter, you have been
introduced to event driven model and object-oriented
programming. Now you should understand what
is meant by the terms object, instance, class,
property, event, and methods.
|
|