WM_ERASEBKGND message

Sent when the window background must be erased (for example, when a window is resized). The message is sent to prepare an invalidated portion of a window for painting.


#define WM_ERASEBKGND                   0x0014

Parameters

wParam

A handle to the device context.

lParam

This parameter is not used.

Return value

Type: LRESULT

An application should return nonzero if it erases the background; otherwise, it should return zero.

Remarks

The DefWindowProc function erases the background by using the class background brush specified by the hbrBackground member of the WNDCLASS structure. If hbrBackground is NULL, the application should process the WM_ERASEBKGND message and erase the background.

An application should return nonzero in response to WM_ERASEBKGND if it processes the message and erases the background; this indicates that no further erasing is required. If the application returns zero, the window will remain marked for erasing. (Typically, this indicates that the fErase member of the PAINTSTRUCT structure will be TRUE.)

Requirements

Minimum supported client

Windows 2000 Professional [desktop apps only]

Minimum supported server

Windows 2000 Server [desktop apps only]

Header

Winuser.h (include Windows.h)

See also

Reference
DefWindowProc
WNDCLASS
Conceptual
Icons
Other Resources
BeginPaint
PAINTSTRUCT

 

 

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