DOCUMENT:Q152000  06-MAY-2001  [visualc]
TITLE   :PRB: Appearance Property Uses Windows 4.0 WS_EX_CLIENTEDGE
PRODUCT :Microsoft C Compiler
PROD/VER:winnt:4.0,4.1
OPER/SYS:
KEYWORDS:kbActiveX kbCOMt kbCtrlCreate kbMFC KbUIDesign kbVC400 kbVC410 kbGrpDSMFCATL

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-------------------------------------------------------------------------------
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 
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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

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

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

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