Q152000: PRB: Appearance Property Uses Windows 4.0 WS_EX_CLIENTEDGE

Article: Q152000
Product(s): Microsoft C Compiler
Version(s): winnt:4.0,4.1
Operating System(s): 
Keyword(s): kbActiveX kbCOMt kbCtrlCreate kbMFC KbUIDesign kbVC400 kbVC410 kbGrpDSMFCATL
Last Modified: 06-MAY-2001

-------------------------------------------------------------------------------
The information in this article applies to:

- The Microsoft Foundation Classes (MFC), used with:
   - Microsoft Visual C++, 32-bit Editions, versions 4.0, 4.1 
-------------------------------------------------------------------------------

SYMPTOMS
========

MFC Controls support a set of standard properties. One of these properties is
Appearance (DISPID_APPEARANCE). Appearance is implemented to give a control a
3-D look. If the control is used on a version of Windows or Windows NT less than
4.0, the Appearance property will not affect the appearance of the control at
run time.

CAUSE
=====

At run time, the Appearance property is implemented in an MFC control by setting
an extended window style WS_EX_CLIENTEDGE. This window style is not supported on
versions of Windows or Windows NT less than 4.0.

RESOLUTION
==========

It is possible to supply your own implementation of the Appearance property
although this technique will not work for subclassed Windows controls.

STATUS
======

This behavior is by design.

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

Using the Class Wizard, add the stock Appearance property but choose Get/Set
methods rather that accepting the stock implementation. In the control, declare
a member variable of type BOOL to represent the Appearance property. The stock
Get/Set functions can be copied and changed slightly to manipulate this variable
as well as handle the property binding requirements. In the Draw function, draw
a 3-D border depending on the value of this variable.

Sample Code
-----------

     // these get and set functions are the same as the original with a minor
     // change (noted in the code)

     short CTestAppearanceCtrl::GetAppearance()
     {
         return m_MyAppearance;
     }

     void CTestAppearanceCtrl::SetAppearance(short nNewValue)
     {
         if (nNewValue != 0 && nNewValue != 1)
             ThrowError(CTL_E_INVALIDPROPERTYVALUE,
                        AFX_IDP_E_INVALIDPROPERTYVALUE);

         // Is the property changing?
         if (m_MyAppearance == nNewValue)
             return;

         if (!BoundPropertyRequestEdit(DISPID_APPEARANCE))
             SetNotPermitted();

     // changed from original
         // do not use the WS_EX_CLIENTEDGE style
         //ASSERT((m_hWnd == NULL) ||
         //  ((GetExStyle() & WS_EX_CLIENTEDGE) == (DWORD)(m_sAppearance ?
         //      WS_EX_CLIENTEDGE : 0)));

         m_MyAppearance = nNewValue;
         SetModifiedFlag();

         //ToggleAppearance(this);
     // end of changes

         OnAppearanceChanged();

         BoundPropertyChanged(DISPID_APPEARANCE);
     }

     void CTestAppearanceCtrl::OnDraw(
                 CDC* pdc, const CRect& rcBounds, const CRect& rcInvalid)
     {
         // TODO: Replace the following code with your own drawing code.
         pdc->FillRect(rcBounds,
              CBrush::FromHandle((HBRUSH)GetStockObject(WHITE_BRUSH)));
         pdc->Ellipse(rcBounds);

         // draw as 3D if m_appearance is set

         if(m_appearance)
         {
             CRect rect(rcBounds);
             pdc->DrawEdge(rect, EDGE_SUNKEN, BF_RECT | BF_ADJUST);
         }
     }

Additional query words: 4.00 4.10 DISPID_APPEARANCE

======================================================================
Keywords          : kbActiveX kbCOMt kbCtrlCreate kbMFC KbUIDesign kbVC400 kbVC410 kbGrpDSMFCATL 
Technology        : kbAudDeveloper kbMFC
Version           : winnt:4.0,4.1
Issue type        : kbprb

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

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 1986-2002.