DOC: CWnd::LockWindowUpdate Does Not Unlock the Window

 Last reviewed: July 31, 1997
Article ID: Q142445 
WINDOWS             | WINDOWS NT
1.00 1.50 1.51 1.52 | 1.00 2.00 2.10 2.20 4.00 kbprg kbdocerr kbdocfix

The information in this article applies to:

  • The Microsoft Foundation Classes (MFC) included with:

    - Microsoft Visual C++ for Windows, versions 1.0, 1.5, 1.51, 1.52 - Microsoft Visual C++, 32-bit Edition, versions 1.0, 2.0, 2.1, 

         2.2, 4.0

SUMMARY

The documentation for CWnd::LockWindowUpdate() states this function will disable or reenable drawing for the CWnd object. In the remarks section, the sentence "Disables or reenables drawing in the given window" is incorrect. Starting with Visual C++ version 2.0, you should use CWnd::UnlockWindowUpdate() to reenable drawing to a window locked with CWnd::LockWindowUpdate().

The documentation error was corrected in Visual C++ 4.1.

MORE INFORMATION

CWnd::LockWindowUpdate() takes no parameters and is implemented as an in-line call to the Windows function ::LockWindowUpdate(). The function ::LockWindowUpdate() is called with the this->m_hWnd parameter which causes the window to be locked. To re-enable drawing, NULL should be passed to ::LockWindowUpdate().

In Visual C++ version 2.0 and later, call CWnd::UnlockWindowUpdate() to reenable drawing to your window. In earlier versions, call the Windows ::LockWindowUpdate( NULL ).

KBCategory: kbprg kbdocerr kbdocfix
KBSubcategory: MfcUI
Additional reference words: 1.00 1.50 2.00 2.10 2.20 4.00 4.10
Keywords : MfcUI kbdocerr kbdocfix kbprg
Technology : kbMfc
Version : 1.00 1.50 1.51 1.52 2.00 2.10 2.
Platform : WINDOWS

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Last reviewed: July 31, 1997
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