Command Bars - Access Violation using a custom form as a submenu

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Access Violation using a custom form as a submenu

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Category: Codejock Products
Forum Name: Command Bars
Forum Description: Topics Related to Codejock Command Bars
URL: http://forum.codejock.com/forum_posts.asp?TID=4542
Printed Date: 21 June 2025 at 4:29am
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Topic: Access Violation using a custom form as a submenu

Posted By: MNovaro
Subject: Access Violation using a custom form as a submenu
Date Posted: 06 July 2006 at 3:46am

Hello,

I found a bug in the CommandBars, using a custom form as a submenu item.

The problem is this:

- create a new VB6 project, with a MDI form in it
- create an MDI child, and add there a command bar object
- write this code in the MDI child, that generates a menu with a custom control in it, that uses a form (this is the same as your SDI sample code):

Set Control = .Add(xtpControlPopup, 0, "Find", -1, False)
Control.BeginGroup = True
Set ControlSearch = Control.CommandBar.Controls.Add(xtpControlCustom, ID_SEARCH_FORM, "Search Form", -1, False)
ControlSearch.Handle = crtlSearchForm.hWnd

- In the MDIForm_Unload event, write this code:

Private Sub MDIForm_Unload(Cancel As Integer)
    Dim frm As Form

    For Each frm In Forms

        Debug.Print frm.Name

        If frm.hWnd <> Me.hWnd Then

            Unload frm

        End If

    Next

End Sub

(I've got a project that simulates the problem, but I can't send it to the forum...)

Ok, now the problem is this: if you open the (custom) menu that contains the form, and then try to close the application, the MDIForm_Unload event generates an Acess Violation error, as soon as it tries to access "frm.Name". If you don't open the custom menu, this does not happens.
This happens only in an MDI environment (no problem using a SDI application).

Any idea on this?

Thanks for any help and kind regards,
Marco

Replies:

Posted By: Oleg
Date Posted: 06 July 2006 at 8:40am

Hello,

Please send sample to mailto:support@codejock.com - support@codejock.com

-------------
Oleg, Support Team
CODEJOCK SOFTWARE SOLUTIONS

Posted By: MNovaro
Date Posted: 06 July 2006 at 8:44am

Ok: I just posted my example application.
To test it, open the menu with the custom form, and then close the application (i.e. close the main MDI form)

Thanks for the support

Posted By: SuperMario
Date Posted: 10 July 2006 at 9:41am

Problem is you have commandbars on MDI child and you then try to unload the custom commandbars control is the MDI parent.

Add this to Form1 (form with commandbars):

Private Sub Form_Unload(Cancel As Integer)
  Dim Control As CommandBarControl
  Set Control = CommandBars.FindControl(, ID_SEARCH_FORM,,True)
  If Not Control Is Nothing Then
    Control.Delete
  End If
End Sub

Private Sub MDIForm_Unload(Cancel As Integer)
    Dim I As Long
    For I = Forms.Count - 1 To 1 Step -1
        Unload Forms(I)
    Next
End Sub