CAD由实体id返回实体对象

{

        if (iCmd == 1)

        {

        var mxOcx = document.all.item("MxDrawXCtrl");

                mxOcx.focus();

        var point1 = mxOcx.GetPoint(null,"n 点取开始点:");

        if(point1 == null)

        {

            return;

        }

        var point2 = mxOcx.GetPoint(point1,"n 点取结束点:");

        if(point1 == null)

        {

            return;

        }

                // 直线的id

                var lineId = mxOcx.DrawLine(point1.x,point1.y,point2.x,point2.y);

                // 为新写的直线写一个字符串扩展数据

                var database = mxOcx.GetDatabase();

                var ent = database.ObjectIdToObject(lineId);

                 if(ent == null)

               {

                  return;

               }

            var exData = mxOcx.Call("Mx_NewResbuf","");

            exData.AddString("TestApp",1001);

                exData.AddString("用户的扩展数据内容。。。",1000);

            ent.SetXData(exData);

    }

}