Using System.Timer;
protected void Application_Start(object sender, EventArgs e)
        {
            Application["MyApp"] = MyApp;
            Timer GetNewDataTimer = new Timer();
            GetNewDataTimer.Interval = 1000;
            //声明时间到时的事件，事件委托
            GetNewDataTimer.Elapsed += new ElapsedEventHandler(OnTimedEvent);
            GetNewDataTimer.AutoReset = true;
            GetNewDataTimer.Enabled = true;
            GetNewDataTimer.Start();
        }

protected void OnTimedEvent(object ob, System.Timers.ElapsedEventArgs e)
        {
            Address_DataLayer.DsPositionAndStaff = Address_DataLayer.GetAllPositionAndStaffDataSet(true);
            Application["AllPositionAndStaff"] = Address_DataLayer.DsPositionAndStaff;
        }

其实就是怎么简单，Global.asax就类似一个类文件，所不同的他是全局类，无论前台如何，它都回做他自己的工作。