private void LoadRealTimeData()
        {
            var query =
                from r in this.dmdc.GetRealTimeQuery()
                where r.VarID == 30
                select r;

            this.RealTimeEntities = this.dmdc.Load<RealTime>(query);
            this.RealTimeEntities.Completed += new EventHandler(RealTimeEntities_Completed);
        }

        void RealTimeEntities_Completed(object sender, EventArgs e)
        {
            List<RealTime> tempList = this.RealTimeEntities.Entities.ToList();
            if (tempList == null || tempList.Count < 1)
                return;
            RealTime rt = tempList[0];
            ///...其它代码
        }