Q184820: FIX: Apply Button on an ATL Control’s Property Page Is Disabled

Article: Q184820
Product(s): Microsoft C Compiler
Version(s): WINDOWS:2.0,2.1
Operating System(s): 
Keyword(s): kbnokeyword kbActiveX kbATL200bug kbATL210bug kbCOMt kbContainer kbCtrl kbPropSheet kbV
Last Modified: 28-JUN-2001

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The information in this article applies to:

- The Microsoft Active Template Library (ATL), versions 2.0, 2.1, used with:
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 4.2b 
   - Microsoft Visual C++, 32-bit Professional Edition, version 4.2b 
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 5.0 
   - Microsoft Visual C++, 32-bit Professional Edition, version 5.0 
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SYMPTOMS
========

When embedding an ATL ActiveX control inside a container application written in
Visual Basic (VB), the Apply button on the control's property page is never
activated even though the property page's dirty flag is set [that is, calling
SetDirty(TRUE)] to enable the button.

CAUSE
=====

Below is the SetDirty() function copied from the Atlctl.h file:

     void SetDirty(BOOL bDirty)
     {
        T* pT = static_cast<T*>(this);
        if (!pT->m_bDirty && bDirty)
           pT->m_pPageSite->OnStatusChange(
              PROPPAGESTATUS_DIRTY | PROPPAGESTATUS_VALIDATE);
        pT->m_bDirty = bDirty;
     }

When OnStatusChange() is called, Visual Basic in turn calls IsPageDirty(), which
returns S_OK if m_bDirty is set to TRUE; otherwise, S_FALSE.

However, as shown above, m_bDirty is not set until OnStatusChanged() returns.

RESOLUTION
==========

Please note that m_bDirty must be set before OnStatusChanged() is called in
SetDirty().

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article. This problem was corrected ATL version 3.0, which
shipped with Visual C++ version 6.0 for Windows.

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

The following are two workarounds:

1. Add an additional call to OnStatusChanged() right after SetDirty() is called.
  Using the ATL Polygon sample code, the change is shown below: "

        LRESULT OnSidesChange(WORD wNotify, WORD wID, HWND hWnd, BOOL&
           bHandled)
        {
           SetDirty(TRUE);
           m_pPageSite->OnStatusChange(
              PROPPAGESTATUS_DIRTY | PROPPAGESTATUS_VALIDATE);
           return 0;
        }

  " (without the quotation marks)

2. Change the SetDirty() function in Atlctl.h to the following: "

        void SetDirty(BOOL bDirty)
        {
           T* pT = static_cast<T*>(this);
           if (pT->m_bDirty != bDirty)
           {
              pT-.m_bDirty = bDirty;
              if (bDirty)
                 pT->m_pPageSite->OnStatusChange(
                    PROPPAGESTATUS_DIRTY | PROPPAGESTATUS_VALIDATE);
           }
        }

  " (without the quotation marks)

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

1. Place an ATL Polygon control on a Visual Basic Form.

2. Display the Polygon control's Property Pages dialog box by selecting the
  (Custom) property from Visual Basic's Properties window.

  NOTE: The Apply button on the Property Pages window is initially disabled.

3. Enter an integer value in the Sides edit box.

  NOTE: The Apply button remains disabled.

(c) Microsoft Corporation 1998, All Rights Reserved. Contributions by Yeong- Kah
Tam, Microsoft Corporation

Additional query words: ocx

======================================================================
Keywords          : kbnokeyword kbActiveX kbATL200bug kbATL210bug kbCOMt kbContainer kbCtrl kbPropSheet kbVBp kbVC420bug kbVC500bug kbVC600fix kbATL300fix kbGrpDSMFCATL 
Technology        : kbVCsearch kbAudDeveloper kbATLsearch
Version           : WINDOWS:2.0,2.1
Issue type        : kbbug
Solution Type     : kbfix

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

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