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Overview |
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Group |
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Quick Info
Windows NT
| Yes
| Win95
| Yes
| Win32s
| Yes
| Import Library
| user32.lib
| Header File
| winuser.h
| Unicode
| No
| Platform Notes
| None
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LockWindowUpdate
The LockWindowUpdate function disables or reenables drawing in the specified window. Only one
window can be locked at a time.
BOOL LockWindowUpdate(
HWND hWndLock
| // handle of window to lock
| );
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Parameters
hWndLock
Specifies the window in which drawing will be disabled. If this parameter is
NULL, drawing in the locked window is enabled.
Return Values
If the function succeeds, the return value is nonzero.
If the function fails, the return value is zero, indicating that an error
occurred or another window was already locked.
Remarks
If an application with a locked window (or any locked child windows) calls the GetDC, GetDCEx, or BeginPaint function, the called function returns a device context with a visible region
that is empty. This will occur until the application unlocks the window by
calling LockWindowUpdate, specifying a value of NULL for hWndLock.
If an application attempts to draw within a locked window, the system records
the extent of the attempted operation in a bounding rectangle. When the window
is unlocked, the system invalidates the area within this bounding rectangle,
forcing an eventual WM_PAINT message to be sent to the previously locked window and its child windows. If
no drawing has occurred while the window updates were locked, no area is
invalidated.
LockWindowUpdate does not make the given window invisible and does not clear the WS_VISIBLE
style bit.
A locked window cannot be moved.
See Also
BeginPaint, GetDC, GetDCEx, WM_PAINT
Related Links
Software for Delphi and C++ Builder developers
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MegaDetailed.NET
More Online Helps
Win32 Programmer's Reference (win32.hlp)
Win32 Multimedia Programmer's Reference (mmedia.hlp)
OLE Programmer's Reference (ole.hlp)
Microsoft Windows Pen API Programmer's Reference (penapi.hlp)
Microsoft Windows Sockets 2 Reference (sock2.hlp)
Microsoft Windows Telephony API (TAPI) Programmer's Reference (tapi.hlp)
Unix Manual Pages
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