关于单文档下绘制动态坐标系,该如何解决

void CPOINT1View::OnMouseMove(UINT nFlags, CPoint point) 
{
    // TODO: Add your message handler code here and/or call default
        CClientDC dc(this);
        CRect rect;
        InvalidateRect(&rect);
        //dc.FillRect(&rect,WHITE_BRUSH);
        GetClientRect(&rect);
        dc.MoveTo(0,point.y);
        dc.LineTo(rect.Width(),point.y);
        //InvalidateRect(&rect);
        dc.MoveTo(point.x,0);
        dc.LineTo(point.x,rect.Height());


        CString str;
    str.Format(_T("x=%d y=%d"),point.x,point.y);
    ((CMainFrame*)GetParent())->m_wndStatusBar.SetWindowText(str);
        //Invalidate();

    CView::OnMouseMove(nFlags, point);
}