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A class is the formal definition of an object. The class is a template for the creation
of the object during programming, and defines the properties and methods that decides how
the object behaves. Class modules is new in Office97. With class modules it's possible to
create your own objects. These objects can have properties and methods like the built-in
objects, and you can create several copies of an object if you need to.
Programmers have managed without class modules earlier, and the reason for using class
modules may not become obvious before you have used class modules for a while. Here are
some of the advantages when using class modules :
- Class modules makes it possible to separate complicated source code for advanced
processes. This makes it easier for other to use the source code without understanding how
the process is performed.
- Class modules makes the development of complicated tasks easier by breaking up the code
in smaller and easier manageable parts. This has been possible earlier, but a class module
forces you to separate the code from the ordinary procedures, resulting in a more obvious
- Class modules let you create reusable components. Because of the obvious separation
between classes and the procedures using them, the classes contains independent code
components that can easily be shared between different projects.
- Class modules is the foundation of other component technologies, Visual Basic can be
used to create X Automation servers and ActiveX controls.
When to use class modules
Here are some examples on when you would want to use class modules :
- Database management
Class modules makes it easier to create objects that can manage a database with VBA. You
can create a class that contains code for reading or writing to a database table. This
class can be used in your macro without the user knowing how and where the data comes
- Wrapping in API procedures
Class modules makes it easier to use Windows API-functions in your macros. Wrapping the
API-functions in a class module makes the development easier for people that are not that
familiar with the more complicated function in Windows.
- Managing reading and writing to text files
This is really not that complicated, but who goes around and remember how this is done in
VBA? By creating a class that manage low level reading to and writing from a
text file, the
properties and methods in the class can easily be used in your macros.
Class modules can also be used to simplify Registry management, and to create new
properties and methods to objects in the applications.
Follow this link to find examples on how to create class modules.
Document last updated 1998-07-07 12:49:20