/// <summary>

         /// 给定桩号值获取纵断面中的高程值，2018年4月21日

         /// 如果给定的桩号在纵断面范围内，则返回对应的高程值，否则返回null

         /// </summary>

         /// <param name="profile"></param>

         /// <param name="station"></param>

         /// <returns></returns>

         public static double? GetElevationFromProfile(this Profile profile, double station)

         {

             double? elevation = null;//定义一个可空类型的数据

             var startStation = profile.StartingStation;

             var endStation = profile.EndingStation;

             if (station >= startStation && station <= endStation)//判断桩号在纵断面桩号范围之内

             {

                 elevation = profile.ElevationAt(station);

             }

             return elevation;

         }

 1         [CommandMethod("getElvFromProfile")]

         public static void GetElvFromProfile()

         {

             Document doc = AcadApp.DocumentManager.MdiActiveDocument;

             Database db = doc.Database;

             Editor ed = doc.Editor;

             CivilDocument civilDoc = CivilApplication.ActiveDocument;

             var opt = new PromptEntityOptions("\n 请拾取一个纵断面对象 ");

             opt.SetRejectMessage("\n 对象必须是纵断面对象");

             opt.AddAllowedClass(typeof(Profile), false);

             var res = ed.GetEntity(opt);

             if (res.Status != PromptStatus.OK)

             {

                 ed.WriteMessage("\n你已经取消了选择");

                 return;

             }

             var doubleResult = ed.GetDouble("\n请输入一个桩号");

             double station = doubleResult.Value;

             using (DocumentLock docLock = doc.LockDocument())

             using (Transaction trans = db.TransactionManager.StartTransaction())

             {

                 Profile profile = trans.GetObject(res.ObjectId, OpenMode.ForRead) as Profile;//获取纵断面对象

                 double? elevation = profile.GetElevationFromProfile(station);//调用扩展方法，获取高程值

                 //ed.WriteMessage(profile.GetElevationFromProfile(station).ToString());

                 ed.WriteMessage(elevation?.ToString());

             }

         }