[AccessD] Just curious

Jim Dettman jimdettman at earthlink.net
Thu Feb 13 05:29:00 CST 2003


John,

<<Classes and Withevents.  POWERFUL stuff!>>

  Yes it is, but I was Access was like this from the ground up.  VFP handles
this a lot better then Access does.

Jim Dettman
President,
Online Computer Services of WNY, Inc.
(315) 699-3443
jimdettman at earthlink.net

-----Original Message-----
From: accessd-admin at databaseadvisors.com
[mailto:accessd-admin at databaseadvisors.com]On Behalf Of John W. Colby
Sent: Wednesday, February 12, 2003 3:33 PM
To: accessd at databaseadvisors.com
Subject: RE: [AccessD] Just curious


John,

This is where a class comes in handy.  The class is passed in a pointer to a
specific control (text box in your example).  The class sinks the events for
whatever control is passed in using Withevents.  So the class can perform
whatever action you find useful.  Now the trick is to build a scanner that
looks through all of the form's controls collection - me.controls(), looking
for all controls of that control type.  Load an instance of the class every
time a text box is found.  Save a pointer to the class in a collection so
that they don't immediately unload again.  Unload the class collection when
the form closes.

Voila, all your text boxes do something.

It's the details of the voila that are the problem.  Once you understand
classes and Withevents, it is trivial to do this.  I can at this point write
a class to do this and a scanner to find and instantiate an instance of the
class for every text box.. in about an hour.

In fact my framework does exactly this.  I have a form class that is loaded
in the form's OnOpen.  The form class has a control scanner that finds every
control.  I have a class for all of the data aware controls.  So the scanner
in the control class loads an instance of the combo class for every combo,
an instance of the text box class for every text box, checkbox class for
every checkbox etc.

And in fact my text box control class has the very behavior you are
discussing (turn the background a different color) so that I can turn on
this behavior with a simple switch.  My combo box class understands what to
do with the combo box NotInList and dblClick.

Etc. Etc.

Classes and Withevents.  POWERFUL stuff!

John W. Colby
Colby Consulting
www.ColbyConsulting.com

-----Original Message-----
From: accessd-admin at databaseadvisors.com
[mailto:accessd-admin at databaseadvisors.com]On Behalf Of John Clark
Sent: Wednesday, February 12, 2003 3:10 PM
To: accessd at databaseadvisors.com
Subject: [AccessD] Just curious


I have a question that really does not pertain to anything that I am
currently doing...other than it may open up some ideas for me...but I
have been curious about it.

If you want to do something to all controls, or all text boxes, on a
form, how would you do this, without placing code behind each and every
control. As I am writing this, it is occurring to me that something like
this may have been posted in the past...don't remember exacts.

Examples of what I would like to do are:

1) I would like to set fields so that when you click on them, with the
mouse, you are taken to the beginning of the field, and maybe the end,
if there were already data existing. I have done this for individual
fields, and the users like it, but I was just to dang lazy to do them
all.

2) There was a program in the past, where for a reason that I no longer
remember, I had programmed each field to become "pale yellow," when it
gained focus, and return to white, when it lost focus. I did this for
each and every field, and it was a pain in the backside.

Again, I am really just curious at this point, but I can think of
several standards that I might input into my programs, once I figure
this out.

Take care!

John W Clark
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