void GetScrollRange( int nBar, int & nMinPos, int & nMaxPos )const
Copies the current minimum and maximum scroll-bar positions for the given scroll bar to the locations specified by lpMinPos and lpMaxPos.
If window does not have a scroll bar, then the GetScrollRange member function copies 0 to lpMinPos and lpMaxPos.
The default range for a standard scroll bar is 0 to 100. The default range for a scroll-bar control is empty (both values are 0).