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Article: Q171972
Product(s): Microsoft Visual Basic for Windows
Version(s): 
Operating System(s): 
Keyword(s): kbGrpDSVB
Last Modified: 11-JAN-2001

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The information in this article applies to:

- Microsoft Visual Basic Control Creation Edition for Windows, version 5.0 
- Microsoft Visual Basic Learning Edition for Windows, version 5.0 
- Microsoft Visual Basic Professional Edition for Windows, version 5.0 
- Microsoft Visual Basic Enterprise Edition for Windows, version 5.0 
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SYMPTOMS
========

A UserControl created in Visual Basic and placed on a form that is opened
modally does not respond to attempts made to disable it. Setting the Enabled
property of the control behaves as expected on a non-modal form, but setting
Enabled = False on a modal form has no effect.

RESOLUTION
==========

You can use the Windows API function EnableWindow to enable/disable the ActiveX
control.

1. In the General Declaration section of the module, place the following
  declaration: (This must be declared as Private if it is included in a form
  module.)

        Private Declare Function EnableWindow Lib "user32" Alias _
           "EnableWindow" (ByVal hwnd As Long, ByVal fEnable As Long) As Long

2. The hWnd property, like all UserControl properties, requires a public
  property method to expose the property as part of the object's interface.
  Since you will not be setting a value, the Property Get is all that is
  needed.

        Public Property Get hWnd() as Long
           hWnd=UserControl.hWnd
        End Property

3. Next, you need to associate this method with the hWnd property of the
  control:

  a. From the Tools menu, select Procedure Attributes.

  b. Select "hWnd" from the Name drop-down list.

  c. Click the Advanced button.

  d. From the Procedure ID drop-down list, choose "hWnd." Click OK.

4. The EnableWindow function can now be called to enable or disable the
  UserControl. To disable the UserControl:

        Dim result as Long
        result = EnableWindow(Me.UserControl1.hWnd, 0)

  To enable the UserControl:

        Dim result as Long
        result = EnableWindow(Me.UserControl1.hWnd, 1)

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article. This bug has been fixed in Visual Basic 6.0.

MORE INFORMATION
================

Steps to Reproduce Behavior
---------------------------

1. Create a new "ActiveX Control" project.

2. Add the following code to the UserControl:

        Public Property Get enabled() As Boolean
             enabled = UserControl.enabled
        End Property

        Public Property Let enabled(vNewValue As Boolean)
             UserControl.enabled = vNewValue
        End Property

        Private Sub UserControl_Click()
            MsgBox "Control is not Disabled."
        End Sub

3. From the Tools menu, select Procedure Attributes.

4. Click the Advanced button.

5. From the Procedure ID drop-down, chose "Enabled." Click OK.

6. Add a "Standard EXE" project.

7. Close the UserControl window, and add the UserControl to Form1.

8. Add two CommandButtons to Form1. Set the following properties.

     Name: Command1    Caption: "Enable Control"
     Name: Command2    Caption: "Disable Control"

9. Add the following code to Form1.

        Private Sub Command1_Click()
           Me.UserControl11.Enabled = True
        End Sub

        Private Sub Command2_Click()
           Me.UserControl11.Enabled = False
        End Sub

10. Add a standard module to the project.

11. Add the following code to Module1:

        Public Sub Main()
               Form1.Show vbModal
             End Sub

12. Run the project.

13. Note that clicking on the button labeled "Disable Control" does not prevent
  the message box from appearing when the UserControl is clicked.

14. Stop the project and open Module1.

15. In Sub Main(), change:

         Form1.Show vbModal

  to:

         Form1.Show

16. Run the project again, and note that the "Disable Control" button now
  functions as expected and the message box does not appear.

Additional query words: kbComp kbCtrl kbVBp kbdsd kbVBp500bug kbVBp600fix kbDSupport kbCtrlCreate kbAPI

======================================================================
Keywords          : kbGrpDSVB 
Technology        : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB500Search kbVBA500Search kbVBA500 kbVB500 kbZNotKeyword3
Issue type        : kbbug
Solution Type     : kbfix

=============================================================================

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Q171972: FIX: Cannot Disable UserControl on Modal Form