Sets the current position of a scroll box and, if requested, redraws the scroll bar to reflect the new position of the scroll box.
BOOL bRedraw = TRUE
Specifies the scroll bar to be set. This parameter can be either of the following:
Specifies the new position of the scroll box. It must be within the scrolling range.
Specifies whether the scroll bar should be repainted to reflect the new scroll-box position. If this parameter is TRUE, the scroll bar is repainted; if FALSE, the scroll bar is not repainted.
The previous position of the scroll box.
Setting bRedraw to FALSE is useful whenever the scroll bar will be redrawn by a subsequent call to another function.