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I have an application under development structured as follows:
Form1 - Welcome splash
Form 2 - General Description
Form 3 - Detail 1
Form 4 - Detail 1.1
...
Form n - Detail 1.1...n
Users will browse in the following sequence:
Form 1 -> Form2 -> ......-> Form n
Concerned with the number of forms that might be opened at the same time (the application will be a very large product catalog), and also concerned with possible memory limitations at the user's machine, I decided that only two forms should be open at the same time:
Form1 - to which a user can return, via a menu placed in the other form being displayed at a given moment, and
Form n - which is where the user is at that given moment.
All other forms shall be unloaded, thus freeing memory.
I wrote the following code:
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Public Sub UnloadNotCurrentForms()
Dim NotCurrentForm As Form
Dim FormName As String
'INITIATE FOR ... NEXT PROCEDURE
For Each NotCurrentForm In Forms
FormName = UCase(NotCurrentForm.Name)
Select Case FormName
'KEEP CURRENTFORM OPEN
Case "FORM1"&".frm", "FORMN"&".frm"
'UNLOAD ALL OTHER FORMS & SET THEM = NOTHING
Case Else
Unload NotCurrentForm
Set NotCurrentForm = Nothing
End Select
Next NotCurrentForm
End Sub
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Please realize that:
1- This code exists in each form
2- "FORM1" & ".frm", "FORMN" & ".frm" are, respectivelly, the Splash form and the form at which the user is when "Formn" is shown.
Although I can run the program while in programmimg mode, as well as after I create the executable, clicking Alt+Tab in W95 let me see that ALL forms previously seen remain open.
In other words, no forms are unloaded or set to Nothing with my code.
I also tried the code:
Case "FORM1", "FORMN"
that is, eliminating the attribute ".frm"
Would anybody tell me what am I doing wrong, please
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Paul Stermann
DSI-Houston
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try:
NextForm.show 'shows the following form before unloading the current one
dim myform as form
for each myform in app.forms
if myform '??? put code here to determine that the user is NOT using it.
...then
unload myform
end if
next myform
this code makes sure that there is only 1 form open at a time.
mail me for deeper explanation if you want it
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Wossname,
Email me: [email protected] :)
[This message has been edited by wossname (edited 11-06-1999).]
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Dear Wossname:
Thank you for your code.
may I assume that the problem with my code is that, instead of
For Each NotCurrentForm In Forms
I should write:
For Each NotCurrentForm In App.Forms???
I posted it here so others can see your solution as well
Thanks
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Paul Stermann
DSI-Houston
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I understand that unloading the non-used forms is not enough to free memory, Should I still Set Forms = Nothing?
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Paul Stermann
DSI-Houston
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your partly right, the CODE of the form stays in memory, Set... = nothing will simply remove the name of the form from the form, so youll have a load of miscellaneous code floating around in memory!
if anyone knows better please jump right in
