Engine 开发中如何往已有IPointCollection中的指定位置处添加多个点

【解决办法】：
AO帮助中IPointCollection.AddPoints下面有这样的说明：
[C#]
When using C# you must use the IGeometryBridge interface to call this method.
所以可以使用IGeometryBridge.InsertPoints方法在指定索引位置添加多个点，示例代码为：

public void InsertPoints()

    {

        IPoint point1 = new PointClass();

        point1.PutCoords(10, 10);

        IPoint point2 = new PointClass();

        point2.PutCoords(20, 20);

        IPoint pointArray = new IPoint[2];

        pointArray[0] = point1;

        pointArray[1] = point2;

        IPointCollection4 pointCollection = new MultipointClass();

        //insert points to pointCollection starting at the given index

        IGeometryBridge geometryBridge = new GeometryEnvironmentClass();

        int index = 0;

        geometryBridge.InsertPoints(pointCollection, index, ref pointArray);

        //insert more points at a different index

        IPoint point3 = new PointClass();

        point3.PutCoords(30, 30);

       IPoint point4 = new PointClass();

        point4.PutCoords(40, 40);

        IPoint secondPointArray = new IPoint[2];

        secondPointArray[0] = point3;

        secondPointArray[1] = point4;

        int secondindex = 1;

        geometryBridge.InsertPoints(pointCollection, secondindex, ref secondPointArray);

    }