protected void Application_Start(object sender, EventArgs e)
        {
            if (HttpRuntime.Cache["ScheduleTask"] == null)
            {
               //第一种办法
                //System.Timers.Timer t = new System.Timers.Timer();
                //t.Elapsed+=new System.Timers.ElapsedEventHandler(test);
                //t.Interval = 1000;
                //t.Enabled = true;
                //GC.KeepAlive(t);
               //第二种办法
                System.Threading.Thread thread = new System.Threading.Thread(test);
                thread.Start();
                //HttpRuntime.Cache["ScheduleTask"] = st;
            }
        }

        void test()
        {
            Log.writeLog("测试成功");
        }

namespace xinchen.Shared.Tools
{
    public class UrlHelper
    {
        public static string Root = HttpContext.Current.Request.ApplicationPath;
···············