[AccessD] Form Lifetime Control Limit (Was: Advice on A2010....)

 The default control names may have something to do with it, but it's not
the entire answer.  I just ran the code below in A2003 and was able to
create 895 controls.   I tried the same code in other versions as well:

A2000 - 800
A2002 - 894
A2007 - 1040
A2010 - 1040

  Apparently the control creation limit is not a hard limit, but based on
some other internal constraint.  This is similar to the table ID limit,
which is stated as 2048, but actually floats a bit.  

  These limits are somehow tied to the way Access internally handles open
objects, but what that process is is un-clear.

Jim.

Public Sub CheckControlCreation()

  Dim frm As Form
  Dim ctlText As Control
  Dim ctlLabel As Control
  Dim intK As Integer

  ' Create form based on Customers form.
  Set frm = CreateForm()

  For intK = 1 To 2000

    ' Create unbound default-size text box in detail section.
    Set ctlText = CreateControl(frm.Name, acTextBox, acDetail, , , 100 +
intK, 100 + intK, 200, 200)

    ' Create child label control for text box.
    Set ctlLabel = CreateControl(frm.Name, acLabel, , ctlText.Name, "", 100,
100)
    
    Debug.Print ctlText.Name, ctlLabel.Name
  
  Next intK

End Sub 

-----Original Message-----
From: accessd-bounces at databaseadvisors.com
[mailto:accessd-bounces at databaseadvisors.com] On Behalf Of William Benson
Sent: Monday, December 12, 2011 07:37 PM
To: Access Developers discussion and problem solving
Subject: Re: [AccessD] Form Lifetime Control Limit (Was: Advice on
A2010....)

Great explanations. Thanks Mark and Ken.
On Dec 12, 2011 6:22 PM, "Darryl Collins" <darryl at whittleconsulting.com.au>
wrote:

> Thanks Ken,
>
> That is a good and clear explanation.
>
> Cheers
> Darryl.
>
> -----Original Message-----
> From: accessd-bounces at databaseadvisors.com [mailto:
> accessd-bounces at databaseadvisors.com] On Behalf Of Kenneth Ismert
> Sent: Tuesday, 13 December 2011 8:27 AM
> To: accessd at databaseadvisors.com
> Subject: Re: [AccessD] Form Lifetime Control Limit (Was: Advice on
> A2010....)
>
> >
> > William Benson:
> > I would love to hear MS's defense of this "lifetime" limitation....
> >
>
> To answer the first part of your question, it all has to do with default
> control names.
>
> When you insert a control in a form, it is given a default name, like
> text10 or label121. The counter that names the controls is the Lifetime
> Control Limit counter. Once it hits 754, it gives up.
>
> The reason for that is name collisions. You can't just reset the counter,
> especially when lots of controls on the form have default names. In this
> scenario, Access might try to name a new control 'text203', and that name
> would already exist. In pathological cases, all possible new names for a
> control could already exist, and then you're stuck.
>
> That is why, in my earlier instructions, I required that you rename all
> controls with default number-suffixed names before resetting the counter.
>
> It was to avoid name collisions.
>
> So, that is the explanation for the Lifetime Control Limit. Is it stupid?
> Yes. Is it lazy? Yes. But it was Microsoft's 'quick and dirty' solution
> for what they surely imagined was going to be a rare event.
>
> -Ken
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