ectEllipse);
        if (circle.PtInRegion(point)) {
            //捕捉鼠标
            SetCapture();
            m_bCaptured = TRUE;
            CPoint pointTopLeft(m_pointTopLeft);
            dc.LPtoDP(&pointTopLeft);
            m_sizeOffset = point - pointTopLeft; 
    
            //设置光标形状为十字状
            ::SetCursor(::LoadCursor(NULL, IDC_CROSS));
        }
    
     CScrollView::OnLButtonDown(nFlags, point);
    }
    
    void CMoveSelObView::OnLButtonUp(UINT nFlags, CPoint point) 
    {
     // TODO: Add your message handler code here and/or call default
     if (m_bCaptured) {
     //释放鼠标捕捉
            ::ReleaseCapture();
            m_bCaptured = FALSE;
        }
    
     CScrollView::OnLButtonUp(nFlags, point);
    }
    
    void CMoveSelObView::OnMouseMove(UINT nFlags, CPoint point) 
    {
    
        if (m_bCaptured) {
     //如果有图形被选中，并且鼠标被捕捉则更新图形位置
            CClientDC dc(this);
            OnPrepareDC(&dc);
            CRect rectOld(m_pointTopLeft, m_sizeEllipse);
            dc.LPtoDP(rectOld);
     //擦除老位置的图形
            InvalidateRect(rectOld, TRUE);
            m_pointTopLeft = point - m_sizeOffset;
            dc.DPtoLP(&m_pointTopLeft);
     //在新位置画图形
            CRect rectNew(m_pointTopLeft, m_sizeEllipse);
            dc.LPtoDP(rectNew);
            InvalidateRect(rectNew, TRUE);
        }
    
    
     CScrollView::OnMouseMove(nFlags, point);
    }