Administrative Notes: : this blog is not finished - this blog on class stuff to be finished next winter hopefully. April 2020 or later... pics in eileenslounge Nick basics
Class Stuff
Introduction To ClassesClass Stuff: VBA Custom Classes & Objects, Class Modules ( Custom Events).
Class Modules.
This is a bad start point. But it seems to be often peoples first experience with this “Class stuff”. Class modules are a small way down from the start of what it is all about, and for the sake of .. I don’t know what .. the subject is often started with the mechanics of setting up a class module. I think using this typical approach and start point seems to detract from someone getting the point.( Its as bit like explaining to someone in detail how to change a wheel on a car when he needs to know how to organize running a taxi company )
I think this results in that somebody trying to learn will .. not see the wood for the trees.
It is true that a class is created by inserting a Class Module (in your VBA project) to which you give a name, but that is just arbitrarily how the mechanics of it have been written.
So I won’t start the story there, by the inserting of a Class Module.
It is a better start point to say…” In VBA you can create your own custom objects by defining classes. Classes act as templates for new objects “
A brief introduction to objects and class objects in VBA. Object Orientated Programming,
If you understand a bit about Object Orientated Programming, OOP, then you will know that it is all about Objects, and an object can be a whole lot of diverse things. OOP is an annoyingly vague concept. The Objects tend to be organised hierarchically starting with the big ones at the top of the hierarchy, and going down through smaller ones.
http://www.excelfox.com/forum/showth...ange#post10809 , , https://imgur.com/tirYIdz http://i.imgur.com/tirYIdz.jpg
Something running parallel to this hierarchical structure which loosely fits into it all, is that we define a Class as a blueprint or Template from which to build one or more objects of that type , or model, or Class. Class is also a vague concept and means like a template, blueprint , or set of instructions or procedures to define how objects built from the Class will look like.
At this point in the discussions, the VB Editor starts getting very misleading: it does not represent clearly the actual structure that we have for two reasons:
_ the positioning of thing is not consistent
_ some things are simply not shown, ( possibly deliberately as we have no access to them. )
Example Model of a workbook
The Workbook
__________________________________________ThisWorkbook
Lets restrict ourselves for the sake of simplicity to having a single workbook as the “start” . Then we could consider a workbook class from which our single workbook is made
ThisWorkbookClassObject___ThisWorkbookObject.
What we see in the VB Editor left hand side explorer window is somehow a representation of the actual Excel object, ( or “instance” of it ) , that we have in front of us. The imprecise definition of objects allows us to consider the code module ( which appears when you double click on ThisWorkbook in the left hand VB Editor explorer window ) as part of workbook object.
In the next post we review the existing Class objects, which inspection of the left hand side explorer window of the VB Editor appears to indicate that we have some access to.
We will see that they are somewhere in between a normal macro code module and a Class module. They could possibly be described as object modules, or Class object modules
Having considered those two existing class related things, we will go on to discuss the other two class related things, which we will see are more close to a "pure" class thing. Those will be the things related to the classic "Class module" and the UserForm
https://web.archive.org/web/20180518...l/classes.aspx
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