Q248655: BUG: ATL Composite Controls Do Not Meet Windows 2000 Logo
Article: Q248655
Product(s): Microsoft C Compiler
Version(s): winnt:6.0
Operating System(s):
Keyword(s): kbAAcc kbActiveX kbATL kbCtrl kbOSWin2000 KbUIDesign kbATL300bug kbGrpDSMFCATL
Last Modified: 07-MAY-2001
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The information in this article applies to:
- Microsoft Visual C++, 32-bit Enterprise Edition, version 6.0
- Microsoft Visual C++, 32-bit Professional Edition, version 6.0
- Microsoft Visual C++, 32-bit Learning Edition, version 6.0
- the operating system: Microsoft Windows 2000
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SYMPTOMS
========
When Windows 2000 is placed into high contrast mode, the ATL Composite controls
do not change their background color. Due to this behavior, any application
using an ATL Composite control fails Windows 2000 logo compliancy.
CAUSE
=====
This is due to a limitation in the ATL framework for ATL Composite controls.
CComCompositeControl handles the WM_CTLCOLORDLG and WM_CTLCOLORSTATIC messages
in the ATL framework and uses the container's ambient background color to paint
the background and any static controls. When Windows 2000 goes into high
contrast mode, the WM_CTLCOLORDLG and WM_CTLCOLORSTATIC messages are sent to the
ATL Composite control. Because the control uses the ambient background color of
the container when the WM_CTLCOLORDLG or WM_CTLCOLORSTATICC message is received,
the messages are not passed on to DefWindowProc(), and the background color and
static control's color does not change.
RESOLUTION
==========
The following modifications can be made to an ATL Composite control to allow it
to pass Windows 2000 logo compliancy.
1. In the composite control's header file and class declaration, add message
handler entries for WM_CTLCOLORDLG and WM_CTLCOLORSTATIC. It should look like
the following:
BEGIN_MSG_MAP(CATLCONTROLObj1)
MESSAGE_HANDLER(WM_CTLCOLORDLG, OnColorDlg)
MESSAGE_HANDLER(WM_CTLCOLORSTATIC, OnColorDlg)
CHAIN_MSG_MAP(CComCompositeControl<CATLCONTROLObj1>)
END_MSG_MAP()
Notice that the MESSAGE_HANDLER() entries appear before the CHAIN_MSG_MAP()
entry. With the entries in this order, the ATL message routing architecture
uses the OnColorDlg() function first before using any message handlers
provided for these messages by the ATL framework.
2. Add a new message handler function, OnColorDlg(), in your ATL composite
control class in the control's header file for the above to entries made to
the message map. The function should have the following prototype and code
inside of it:
LRESULT OnColorDlg(UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL& bHandled)
{
HIGHCONTRAST highcontrast = { 0 };
highcontrast.cbSize = sizeof(HIGHCONTRAST);
if (SystemParametersInfo(SPI_GETHIGHCONTRAST, sizeof(HIGHCONTRAST), &highcontrast, 0))
{
if (highcontrast.dwFlags & HCF_HIGHCONTRASTON) //high contrast on?
return DefWindowProc(); //Ignore ambient back color and pass to system.
}
//else, must be OS where SPI_GETHIGHCONTRAST not available
//Set bHandled to FALSE to allow the message to keep on being routed to base
bHandled = FALSE;
return FALSE; //Let message continue to base class.
}
3. Save the header file and rebuild the control.
4. Insert the control into Test Container and place Windows 2000 into high
contrast mode. You can place Windows 2000 into high contrast mode using the
following keystrokes: LEFT ALT + LEFT SHIFT + PRINT SCREEN.
Notice that the ATL Composite control's background and any static controls change
color when Windows 2000 is placed into high contrast mode.
STATUS
======
Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article.
MORE INFORMATION
================
Steps to Reproduce Behavior
---------------------------
1. Create a new ATL project using the ATL COM AppWizard. Give the project the
name "TestHighCotrast" and click OK.
2. On the ATL COM AppWizard Step 1 of 1 screen, accept the defaults and click
Finish.
3. From the Insert menu, select New ATL Object.
4. Click Controls under the Category section. Click Composite Control under the
Objects section. Click Next.
5. In the ATL Object Wizard Properties dialog box, give the short name for the
control the name TestHighContrastControl. Accept the defaults for the
remaining settings and click OK.
6. Build the project.
7. Insert the control into Test Container and place Windows 2000 into high
contrast mode. You can place Windows 2000 into high contrast mode using these
keystrokes: LEFT ALT + LEFT SHIFT + PRINT SCREEN.
Notice that the ATL Composite control's background and any static controls on the
control do not change color when Windows 2000 is placed into high contrast mode.
REFERENCES
==========
Windows Logo Program
Additional query words: windows 2000 logo fail compliancy comply compliant accessability high contrast
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Keywords : kbAAcc kbActiveX kbATL kbCtrl kbOSWin2000 KbUIDesign kbATL300bug kbGrpDSMFCATL
Technology : kbVCsearch kbOSWin2000 kbAudDeveloper kbOSWinSearch kbVC600 kbVC32bitSearch
Version : winnt:6.0
Issue type : kbbug
Solution Type : kbpending
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