An application sends the SBM_SETPOS message to a scroll bar control to set the position of the scroll box (thumb) and, if requested, redraw the scroll bar to reflect the new position of the scroll box.
SBM_SETPOS
wParam = (WPARAM) nPos; // new position of scroll box
lParam = (LPARAM) (BOOL) fRedraw; // redraw flag
Parameters
nPos
Specifies the new position of the scroll box. It must be within the scrolling range.
fRedraw
Specifies whether the scroll bar should be redrawn to reflect the new scroll box position. If this parameter is TRUE, the scroll bar is redrawn. If it is FALSE, the scroll bar is not redrawn.
Return Values
If the position of the scroll box changed, the return value is the previous position of the scroll box; otherwise, it is zero.
Remarks
If the scroll bar control is redrawn by a subsequent call to another function, setting the fRedraw parameter to FALSE is useful.
See Also