Class module
You can go a long way in Access database development without really using the
object orientated features of Access VBA but a class module is a good way of
improving the design of your database and making the code easier to maintain.
On a small project, the class module gathers everything you need for a
particular task into one self-contained unit so that it's easier to find. On
a larger scale the self-contained class module can be reused if the same
task comes up in different projects.
To be fair, this is something we've always been able to do with procedures
and functions in a code module but the concept of object orientation makes
it easier to develop, test and maintain something that does not depend on
any external features.
Creating a class module
A class module is just VBA code and it appears in the same category
as a regular code module on the screen. The only obvious difference is the
icon - the prefix "cls" in the screenshot above is just my own naming
preference.
A class module can be created from the main database window or from the
VBA editor. It's easy in the editor, just select
from the
menu. It's less obvious from the
main window because there's no mention of class modules at all. The trick
is to go to the area at the right-hand end of
the menu bar. Click on
and a menu will appear with
as an option. Click this
and an empty edit window will open.
Oddly enough, once you've created a new class module the class icon will
replace the macro icon on the ribbon.
The next page shows how to build a class that brings something of a dotNet flavour to
calling the
MessageBox
function in Access.
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