WM_MBUTTONUP

The WM_MBUTTONUP message is posted when the user releases the middle mouse button while the cursor is in the client area of a window. If the mouse is not captured, the message is posted to the window beneath the cursor. Otherwise, the message is posted to the window that has captured the mouse.

WM_MBUTTONUP 
fwKeys = wParam;        // key flags 
xPos = LOWORD(lParam);  // horizontal position of cursor 
yPos = HIWORD(lParam);  // vertical position of cursor 
 

Parameters

fwKeys

Value of wParam. Indicates whether various virtual keys are down. This parameter can be any combination of the following values:

Value	Description
MK_CONTROL	Set if the ctrl key is down.
MK_LBUTTON	Set if the left mouse button is down.
MK_RBUTTON	Set if the right mouse button is down.
MK_SHIFT	Set if the shift key is down.

xPos

Value of the low-order word of lParam. Specifies the x-coordinate of the cursor. The coordinate is relative to the upper-left corner of the client area.

yPos

Value of the high-order word of lParam. Specifies the y-coordinate of the cursor. The coordinate is relative to the upper-left corner of the client area.

An application can use the MAKEPOINTS macro to convert the lParam parameter to a POINTS structure.

QuickInfo

  Windows NT: Requires version 3.1 or later.
  Windows: Requires Windows 95 or later.
  Windows CE: Unsupported.
  Header: Declared in winuser.h.

See Also

Mouse Input Overview, Mouse Input Messages, GetCapture, MAKEPOINTS, POINTS, SetCapture, WM_MBUTTONDBLCLK, WM_MBUTTONDOWN