Windows Mobile 6.5
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This function adds a rectangle to the specified window's update region. The update region represents the portion of the window's client area that must be redrawn.

BOOL InvalidateRect( 
  HWND hWnd, 
  const RECT* lpRect, 
  BOOL bErase


Handle to the window whose update region has changed.

If you pass a NULL value for this parameter InvalidateRect takes no action and returns FALSE.


Long pointer to a RECT structure that contains the client coordinates of the rectangle to be added to the update region.

If this parameter is NULL, the entire client area is added to the update region.


Boolean that specifies whether the background within the update region is to be erased when the update region is processed.

If this parameter is TRUE, the background is erased when the BeginPaint function is called.

If this parameter is FALSE, the background remains unchanged.

Nonzero indicates success.

Zero indicates failure.

To get extended error information, call GetLastError.

To get extended error information, call GetLastError.

The hWnd parameter cannot be NULL.

The invalidated areas accumulate in the update region until the region is processed when the next WM_PAINT message occurs or until the region is validated by using the ValidateRect function.

The system sends a WM_PAINTmessage to a window whenever its update region is not empty and there are no other messages in the application queue for that window.

If the bErase parameter is TRUE for any part of the update region, the background is erased in the entire region, not just in the given part.

Librarycoredll.lib, Winmgr.lib
Windows Embedded CEWindows CE 1.0 and later
Windows MobileWindows Mobile Version 5.0 and later

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