MxDrawEntity ent = (MxDrawEntity)axMxDrawX1.GetEntity("选择样条线");
        if (ent == null)
            return;

        if (ent is MxDrawSpline)
        {
            MxDrawSpline spl = (MxDrawSpline)ent;
            MxDrawPoints fitPoints = spl.GetFitPoints();

            for (int i = 0; i < fitPoints.Count; i++)
            {
                MxDrawPoint pt = fitPoints.Item(i);

                MessageBox.Show(pt.x.ToString() + "," + pt.y.ToString());
            }
         }