The WM_MOVING message is sent to a window that the user is moving. By processing this message, an application can monitor the size and position of the drag rectangle and, if needed, change its size or position.

fwSide = wParam; // edge of window to be moved
lprc = (LPRECT) lParam; // screen coordinates of drag rectangle

Parameters

fwSide

Value of wParam. Indicates which edge of the window is being moved. This parameter can be a combination of the following values:

Value Meaning
WMSZ_BOTTOM Bottom edge
WMSZ_BOTTOMLEFT Bottom-left corner
WMSZ_BOTTOMRIGHT Bottom-right corner
WMSZ_LEFT Left edge
WMSZ_RIGHT Right edge
WMSZ_TOP Top edge
WMSZ_TOPLEFT Top-left corner
WMSZ_TOPRIGHT Top-right corner

oder

The WM_SIZE message is sent to a window after its size has changed.

WM_SIZE
fwSizeType = wParam; // resizing flag
nWidth = LOWORD(lParam); // width of client area
nHeight = HIWORD(lParam); // height of client area

Parameters

fwSizeType

Value of wParam. Specifies the type of resizing requested. This parameter can be one of the following values:

Value Meaning
SIZE_MAXHIDE Message is sent to all pop-up windows when some other window is maximized.
SIZE_MAXIMIZED Window has been maximized.
SIZE_MAXSHOW Message is sent to all pop-up windows when some other window has been restored to its former size.
SIZE_MINIMIZED Window has been minimized.
SIZE_RESTORED Window has been resized, but neither the SIZE_MINIMIZED nor SIZE_MAXIMIZED value applies.

oder

The WM_MOVE message is sent after a window has been moved.

WM_MOVE
xPos = (int) LOWORD(lParam); // horizontal position
yPos = (int) HIWORD(lParam); // vertical position

Parameters

xPos

Value of the low-order word of lParam. Specifies the x-coordinate of the upper-left corner of the client area of the window.

yPos

Value of the high-order word of lParam. Specifies the y-coordinate of the upper-left corner of the client area of the window.

Return Values

If an application processes this message, it should return zero.

Remarks

The xPos and yPos parameters are given in screen coordinates for overlapped and pop-up windows and in parent-client coordinates for child windows.
An application can use the MAKEPOINTS macro to convert the lParam parameter to a POINTS structure.

WM_SIZE und WM_MOVE werde auch immer automatisch am Anfang gesendet, wenn das Fenster erstmalig erstellt wird.