WM_WINDOWPOSCHANGED

The WM_WINDOWPOSCHANGED message is sent to a window whose size, position, and/or Z order has changed as a result of a call to SetWindowPos or other window-management function.

Parameters

wParam

This parameter is not used.

lParam

Points to a WINDOWPOS data structure that contains information about the window's new size and position.

The WINDOWPOS structure has the following form:

typedef struct tagWINDOWPOS { /* wp */

HWND hwnd;

HWND hwndInsertAfter;

int x;

int y;

int cx;

int cy;

UINT flags;

} WINDOWPOS;

Return Value

An application should return zero if it processes this message.

Comments

The DefWindowProc function, when it processes the WM_WINDOWPOSCHANGED message, sends the WM_SIZE and WM_MOVE messages to the window. These messages are not sent if an application handles the WM_WINDOWPOSCHANGED message without calling DefWindowProc. It is more efficient to perform any move or size change processing during the WM_WINDOWPOSCHANGED message without calling DefWindowProc.