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

• The Microsoft Active Template Library (ATL), versions 2.0, 2.1, used with:
  • Microsoft Visual C++, 32-bit Editions, versions 4.2b, 5.0

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;
   } 

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;
         } 




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);
            }
         } 

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.

Additional query words: ocx

Keywords : kbnokeyword kbActiveX kbATL200bug kbATL210bug kbCOMt kbContainer kbCtrl kbPropSheet kbVBp kbVC420bug kbVC500bug kbVC600fix kbATL300fix kbGrpMFCATL
Version : WINDOWS:2.0,2.1
Platform : WINDOWS
Issue type : kbbug