# Function Reference

# _WinAPI_InvalidateRect

Adds a rectangle to the specified window's update region

#include <WinAPISysWin.au3>
_WinAPI_InvalidateRect ( $hWnd [, $tRECT = 0 [, $bErase = True]] )

## Parameters

$hWnd | Handle to windows or a GUI Control ID
$tRECT | [optional] $tagRECT structure that contains the client coordinates of the rectangle to be added to the update region. If this parameter is 0 the entire client area is added to the update region.
$bErase | [optional] 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.

## Return Value

Success: | True
Failure: | False, call _WinAPI_GetLastError() to get extended error information

## Related

$tagRECT

## See Also

Search InvalidateRect in MSDN Library.