[AccessD] Naming Conventions

...lol ...Code Boy never comes down to earth long enough to converse with 
mere mortals :)

William

----- Original Message ----- 
From: "Drew Wutka" <DWUTKA at marlow.com>
To: "Access Developers discussion and problem solving" 
<accessd at databaseadvisors.com>
Sent: Friday, March 16, 2007 10:46 AM
Subject: Re: [AccessD] Naming Conventions


>I hope you don't say the same about me! ;)
>
> Drew
>
> -----Original Message-----
> From: accessd-bounces at databaseadvisors.com
> [mailto:accessd-bounces at databaseadvisors.com] On Behalf Of William
> Hindman
> Sent: Thursday, March 15, 2007 9:41 PM
> To: Access Developers discussion and problem solving
> Subject: Re: [AccessD] Naming Conventions
>
> ...and then there are those of us who's head spins when JC starts
> thumpin'
> ...those who just manage to make it work without rebuilding the Pyrimids
>
> first ...I admire what JC does and I've learned more than a few things
> from
> him over the years that are part of my standard library ...but holy cow,
>
> trust me, it is still possible to build good, sound, responsive apps
> fairly
> rapidly without selling your first born child to the gods of Access :)
>
> ...so if any of you lurkers out there are thinking how much JC's posts
> sound
> like those you find over on the C++ forums, don't despair ...he does
> come
> down to earth often enough to enlighten even those of us who need a
> dictionary to translate his occasional flights into the nether world :)
>
> William Hindman
>
> ----- Original Message ----- 
> From: "JWColby" <jwcolby at colbyconsulting.com>
> To: "'Access Developers discussion and problem solving'"
> <accessd at databaseadvisors.com>
> Sent: Thursday, March 15, 2007 2:18 PM
> Subject: Re: [AccessD] Naming Conventions
>
>
>> >..I am currently learning about classes from the information on your
>> website :-)
>>
>> Uh oh.
>>
>> ;-)
>>
>> Welcome to the next level of programming.  Classes really solve a host
> of
>> "container" problems that simply can't be done any other way.
>>
>> Back in about 2000, before Shamil opened my eyes to classes (and
>> withevents)
>> I used collections and collections of collections to hold objects.  It
>> worked but was sooooooo clumsy.  Now I start with a base class (or
>> sometimes
>> a module) and that class holds collections which hold class instances.
>>
>> For example as everyone knows by now I have a framework.  One of the
> base
>> units of the framework is a dclsFrm which wraps the form object.  BTW,
> in
>> THIS CASE, the d is not a type prefix at all, it an homage to Shamil
> who
>> called his Withevent programming "DEEP" programming.  So a dclsXXXX is
> a
>> class which will sink (and possibly source) events inside the class.
> IOW
>> it
>> is a DEEP class.  Just a way of paying my respects to Shamil.  Sinking
> and
>> sourcing events in classes is so incredibly powerful that I simply
> can't
>> imagine not doing so now.
>>
>> So I have a dclsFrm class which is dimensioned in the form's
>> "code-behind-form's" class module header and initialized in the OnOpen
> of
>> the form.  The form passes in a reference to itself to the dclsFrm
> that it
>> just instantiated.  The dclsFrm then sets the pointer passed in ("its"
>
>> form)
>> into a module level global at the top of the class, declared
> WithEvents.
>> Declaring the form variable WithEvents tells VB that this class
> expects to
>> sink events from the form.  I then create event sinks for all of the
>> form's
>> events.
>>
>> One of the KEY constructs of dclsFrm is a control scanner which is
> called
>> from the Init().  That scanner looks for every single control on the
> form
>> (iterates the controls() collection of the form).  Each time it finds
> a
>> control, a huge case statement asks "what kind of control is this" and
>
>> loads
>> a wrapper class for each control.  So my framework also has a dclsCbo,
>> dclsTxt, dclsCmd etc.  As the scanner finds a textbox, it instantiates
> a
>> dclsTxt and initializes it, passing in a pointer to that text box
> control.
>> Now that it has a dclsTxt for that text box, it needs a place to store
> the
>> class pointer.  For this I use a collection up in the dclsFrm's
> header.
>> Every control class wrapper gets stored in this collection, keyed on
> the
>> control's name.  Since the control name is always unique, the form
> itself
>> (or dclsFrm) can always look into this collection using the control's
> name
>> to find the wrapper class for that control.
>>
>> I also have a few special purpose collections which hold specific
> types of
>> controls but the point here is that the dclsFrm can use collections to
>
>> hold
>> entire collections of other classes.  In fact those "child" classes
> can
>> also
>> have collections which store things.  For example I have a dctlTab
> which
>> has
>> a collection which holds... dclsTabPage instances.
>>
>> Each class sinks the events of its "wrapped" control and implements
>> generic
>> behaviors that I find so common that I want it always available.
>>
>> When you read this, the biggest thing to take away is that I did not
> write
>> all of this stuff in a week or even a month.  I add functionality to
> my
>> framework as I run into a need for it.  One day I decided that I
> really
>> needed some basic "form wrapper" functionality.  I found myself
> writing a
>> TON of similar code in every form - stuff to find specific records
> etc.
>> What better place to put it than in a class which wraps the form and
>> provides that functionality to ANY form that wants that kind of
>> functionality.  Dimension my dclsFrm, initialize it and voila, all of
> that
>> code is now "locked and loaded", ready to be used by the form, in fact
> it
>> can happen completely automatically in many cases.
>>
>> One day I decided that it would be nice to have my combo's just
>> automatically handle NotInList (and dbl-click) events and either open
> a
>> form
>> for adding / editing the table behind the form (dbl-click), or for
> simple
>> tables, just add a new entry when the user typed in something not
> already
>> in
>> the list (NotInList).  Sure, I could dbl click each and every combo's
>> NotInList property and call a function that does that but why?  A
> combo
>> wrapper class can do all that for me.  Now that I have a combo wrapper
>
>> class
>> (dclsCbo) how do I get it to load automatically?  Hmmm... My dclsFrm
> needs
>> a
>> control scanner...
>>
>> Now my dclsFrm loads an instance of dclsCbo for every combo.  Hmmm...
> How
>> about my text boxes?  I want the text boxes to change background color
> as
>> it
>> gets the focus and revert back to the old color when it loses the
> focus.
>> Easy in a dclsTxt.  Sink the OnEnter and OnExit of the text box and
> cause
>> it
>> to change the background color.  Hmm... Now go back to my dclsCbo and
> make
>> it do the same thing...  Edit my control scanner in dclsFrm to load
> the
>> text
>> box classes.  Hmmm... I want the combo control to change the label
> back
>> color if it handles the NotInList so that there is a visual cue to the
>
>> user
>> to expect this.  Have the dclsCbo grab a pointer to its label and then
> set
>> the label's back color as the combo initializes IF it is going to
> handle
>> the
>> not-in-list.
>>
>> And over time you can build up a really nifty framework that just
>> automates
>> all of that lowly programming stuff that you used to have to do
> manually.
>> Load dclsFrm, it loads all the dclsXXX control wrappers, they handle
> the
>> details.  Just that easy!  I can literally have about 20-30 lines of
> code
>> in
>> a form (in the OnOpen) and have it doing all kinds of stuff that I
> want it
>> to do.  It would look like magic to the non class programmer but it is
>
>> just
>> plain old programming, just tied to events in the object wrapper class
>> instead of in each form.
>>
>> How would you like to be able to apply a uniform format to dates in
> all
>> forms, and be able to change them by changing a record in a table?  If
> you
>> use bound forms and wrapper classes it is almost trivial.  The form's
>> recordset clone can be manipulated as a dao.recordset object.  Each
>> control
>> is bound to a specific field and thus "knows" it's field name in the
>> recordset.  So any control can get the properties collection for its
> field
>> from the dclsFrm (its parent), find out what the data type is, and if
> the
>> data type is a date, apply a specific date format to it.  If you use
> my
>> SysVars method, you load the date format as a sysvar (a record in a
> table)
>> and the control simply looks up the required date format in the SysVar
>> class.  All done by the dclsTxt class as it loads, automatically (to
> the
>> application) because the dclsFrm has a control scanner in it.
>>
>> Now imagine trying to do this kind of stuff without classes.  It ain't
>
>> easy
>> and it ain't fun, and in fact it is so hard you just don't do it.
> With
>> classes / WithEvents it is easier and lots of fun.
>>
>> John W. Colby
>> Colby Consulting
>> www.ColbyConsulting.com
>>
>> -----Original Message-----
>> From: accessd-bounces at databaseadvisors.com
>> [mailto:accessd-bounces at databaseadvisors.com] On Behalf Of Barbara
> Ryan
>> Sent: Thursday, March 15, 2007 12:10 PM
>> To: Access Developers discussion and problem solving
>> Subject: Re: [AccessD] Naming Conventions
>>
>> Thanks for all the info.  I have always used the "standard" tags and
>> prefixes (i.e., "tbl", "frm", cbo, etc.) but figured it was time to
> become
>> more descriptive!
>>
>> John C. --- thanks for your explanation of prefixes....I am currently
>> learning about classes from the information on your website :-)
>>
>> Thanks!
>> Barb Ryan
>>
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>>
>
>
>
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