PRB: DoSuperclassPaint Calls WM_PRINT for Windows 95

The information in this article applies to:

• The Microsoft Foundation Classes (MFC) included with: Microsoft Visual C++, 32-bit Edition, version 4.0

SYMPTOMS

In some cases, you may need to take a window's custom control and subclass it with an OLE control. However, when the control is built using MFC 4.0 and being used in Windows 95, the OLE control may paint incorrectly.

CAUSE

A typical OnDraw() handler in an OLE control that subclasses a window's custom control makes a call to DoSuperclassPaint(). In Windows 95, The MFC 4.0 implementation of DoSuperClassPaint() has been changed to send a WM_PRINT message to the custom control's window procedure instead of a WM_PAINT message. If the original custom control does not handle WM_PRINT, the OLE control will not paint correctly.

RESOLUTION

It is necessary for the original custom control to handle the WM_PRINTCLIENT message, which is what the DefWindowProc sends in response to receiving a WM_PRINT message. The WM_PRINTCLIENT message should be handled in the same manner as the WM_PAINT message except that the calls to BeginPaint() and EndPaint() should be removed.

STATUS

This behavior is by design.