[AccessD] Open Multiple Instances of a Form and passing a parameter

>
> Stuart McLachlan:
> ...
> Perhaps John and Kenneth can explain what they think the Tag property is
> for.
> ...
> Also, why they think that 62 lines of code in two different location is
> not *ugly* ...
>

First, you have to have *some* code to run multiple form instances. This is
the 'bare bones' required for real, predictable multi-form functionality.
You might find some fat to trim on that code, but not much.

But the main point is: why is the Tag property 'bad'? To paraphrase John's
response, Tag is a global form property, and as such it can be set by any
code anywhere at any time, even when the form is closed! It is the 'go to'
fix for any and all problems where 'some kind of information' is required
that doesn't fit in the normal form framework.

So, the odds are good that if you rely on Tag (or any other kind of shared
global) in a project of any size, you or someone else will write code that
steps on functionality required in other parts of the program..

This is called 'incidental complexity' -- the unintended problems
introduced by a system of code or language. It is the time you spend fixing
or working around stuff  that is improperly designed. It is a drag on your
productivity.

There is a software development concept that covers this called Law of
Demeter, or Principle of Least Knowledge. Basically, it says 'code
shouldn't get into other code's business'. In this style of writing code,
using class properties like Tag assumes too much knowledge, or 'tight
coupling' of objects with code.

My sample code was written with these guidelines in mind. It is loosely
coupled: all interaction between caller and form is done using public
functions. It passes TYPED VARIABLES to the form, with no need for parsing
or conversion. Plus, it is such a nice platform to expand on to implement
more complex form functionality. All code that interacts with the form
resides in one companion module.

In short, using Tag is fine if your standard is 'it usually works', or 'its
OK if it fails unexpectedly'. But I want GUARANTEES that my code will work,
or fail immediately.

-Ken