CAD .net二次开发直线转化多段线（Polyline）

Point3dCollection col_point = new Point3dCollection(); Line ent_line = item as Line;                    Point3d startPoint = ent_line.StartPoint;                    Point3d endPoint = ent_line.EndPoint;                    col_point.Add(startPoint);                    col_point.Add(endPoint);                    Polyline poly = new Polyline();                    poly.Color = reg.Color;                    poly.Closed = true;                    poly.LineWeight = reg.LineWeight;                    poly.LinetypeId = reg.LinetypeId;                    PolylineTools.CreatePolyline(poly, col_point);                    btr.AppendEntity(poly);                    trans.AddNewlyCreatedDBObject(poly, true);