Pause VBA while dll function runs

Hi,
I have created a VB6 dll which processes files, running through a few forms
and subs before terminating. Upon finishing, I want the VBA program which
called it to continue.
How do you pause a VBA program while a called VB dll does its thing?

Thanks,
Jon Rasmussen

 

You do not have to anything to "pause" VBA, since the ActiveX dll used in
your VBA process is "in process" operation, just like executing a procedure
of VBA. Take following VBA procedure as an example,

Private Sub DoSomething()

'Do something first - pure VBA opeation

Dim obj As MyDll.MyObject
Set obj = New MyDll.MyObject 'Call object in you dll
obj.DoLengthyProcess 'Do lengthy process, it run
inside VBA process boundary

End Sub

The potential problem is that when the length process (whether it is code in
DLL or pure VBA code, the computer may look frozen. You better add some
visual indicator to inform user something is going on. With VBA code, it is
easy to put a label on form and update label's caption periodically (or use
a progressbar, but license could be an issue). With dll, how do you return a
progress indicator to its calling VBA?
I usually add an optional argument (Label, or ProgressBar) to the lenthy
process method:

Class MyObject
....
Public Sub DoLengthyProvess(arg1 As ...,...,Optional promptLabel As Lable)

End Sub

In this method, if the optinal argument is supplied, then it gets updated
periodically. So, when I need visual indicator on a form when call the
DoLengthyProcess(), I simply pass a label (or progressbar) on the form in
the method call. Oh, do not forget call Label.Refresh, or DoEvents to
refresh the Label inside the method.

 

Thanks Norman, I appreciate your time.

You're right, I was looking at it the wrong way.
The snippets of code were great.

Thanks,

Jon Rasmussen

 

I have struck a problem:

When I try to run the dll program, which has multiple forms, I get the
message
Can't show non-modal form when modal form is displayed.

The code that is calling the dll is:

Private Sub CB_REDUCE_SURVEY_Click()
surveyreduce.fn_reduce_survey
End Sub

which is command button on a form. If I tell the form to hide itself, the
program runs, but then the form menu will not be displayed when the dll
program is completed.

Any hints wiould be appreciated.

Jon Rasmussen

 

Hi Jon,

All you need in general terms is:

Private Sub CB_REDUCE_SURVEY_Click()
Me.Hide
surveyreduce.fn_reduce_survey
Me.Show
End Sub

--


Laurie Comerford
CADApps
www.cadapps.com.au

Me.Hide

 

Hi Laurie,

Except the program doesn't wait for the dll to finish before it redisplays
the calling form, so I end up with the dll form in the background.

Jon Rasmussen

 

Since UserForm in Acad is usually shown as modal form (unless you show it as
modeless with AcFocusControl applied on Acad2002/2004, which I have never
used), if you wnat to open another form without closing/hiding the UserForm,
you must open it as modal form. See following code sample:

In ActiveX dll project:

The Class called DllFormTest:
===========================
Option Explicit

Private dlg As dlgTest

Public Function GetDialogBoxReturnedValue() As String

Set dlg = New dlgTest
dlg.Show vbModal

Dim ret As String
ret = dlg.DialogResult

Unload dlg

GetDialogBoxReturnedValue = ret

End Function
================================

Here is the form in *.dll project that will be opened as dialog box:
This is a blank form with two buttons: OK and Cancel
==================================
Option Explicit

Private strReturn As String

Public Property Get DialogResult() As String
DialogResult = strReturn
End Property

Private Sub CancelButton_Click()
strReturn = "DialogBox is cancelled!"
Me.Hide
End Sub

Private Sub OKButton_Click()
strReturn = "DialogBox is OKed!"
Me.Hide
End Sub
=================================

After compiling the *.dll project, now in Acad, you call the dll class to
show a dialog form by clicking a button on the UserForm:
==============================

Private Sub CommandButton1_Click()

Dim dlg As DllForm.DllFormTest
Dim dlgResult As String

dlg=New DllForm.DllFormTest
dlgResult=dlg.GetDialogBoxReturnedValue

MsgBox dlgResult

'Do something depending on the dialog result

End Sub
=============================

HTH

 

HTH
This helped heaps!!

Thanks Norm.

I can't help feeling that I am missing something however. I have a VBA menu,
which activates this dll programme (which has it own forms as it is also a
stand alone program), and I want the calling vba menu to come back when the
dll is finished. How do programers normally do this?

Jon

 

Hi Jon,

I do it exactly as I posted above. I do not change the modality of the
forms in either program and have never had a problem.

--


Laurie Comerford
CADApps
www.cadapps.com.au