DOCUMENT:Q171972  11-JAN-2001  [vbwin]
TITLE   :FIX: Cannot Disable UserControl on Modal Form
PRODUCT :Microsoft Visual Basic for Windows
PROD/VER:
OPER/SYS:
KEYWORDS:kbGrpDSVB

======================================================================
-------------------------------------------------------------------------------
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 
-------------------------------------------------------------------------------

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

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

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS
PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND.  MICROSOFT DISCLAIMS
ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  IN NO
EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR
ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL,
CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF
MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.  SOME STATES DO NOT ALLOW THE EXCLUSION
OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES
SO THE FOREGOING LIMITATION MAY NOT APPLY.

Copyright Microsoft Corporation 2001.