循环导致cad崩溃，敬请高手指点。

lincoln_ma

刚开始用C#开发AutoCAD，向绘制几条Pline，但在使用while、for等循环的过程中，总是导致cad崩溃。

发生问题的代码如下：

                Polyline[] MidBox = new Polyline[5];
                for (int ILoop = 0; ILoop < 5; ILoop++)
                {
                    MidBox[ILoop].AddVertexAt(0, new Point2d(0, 0), 0, 0, 0);
                    MidBox[ILoop].AddVertexAt(1, new Point2d(1, 1), 0, 0, 0);
                    MidBox[ILoop].AddVertexAt(2, new Point2d(2, 2), 0, 0, 0);
                    MidBox[ILoop].AddVertexAt(3, new Point2d(3, 3), 0, 0, 0);
                    MidBox[ILoop].AddVertexAt(4, new Point2d(4, 4), 0, 0, 0);
                    MidBox[ILoop].AddVertexAt(5, new Point2d(5, 5), 0, 0, 0);
                    ////向块表记录中添加边箱线
                    //btr.AppendEntity(MidBox[ILoop]);
                    //trans.AddNewlyCreatedDBObject(MidBox[ILoop], true);
                }

请问是怎么回事？

雪山飞狐_lzh

这是基本语法问题

Polyline[] MidBox = new Polyline[5];

这里创建了5个元素的Polyline的数组，但每个元素都是空值

for循环开始直接调用空值MidBox[ILoop]，自然崩溃

解决：在循环开始加

MidBox[ILoop] = new Polyline();