public class WebTimer_AutoRepayment
{
    static WebTimer_AutoRepayment()
    {
        _WebTimerTask = new WebTimer_AutoRepayment();
    }
    /// <summary>
    /// 实例化
    /// </summary>
    /// <returns></returns>
    public static WebTimer_AutoRepayment Instance()
    {
        return _WebTimerTask;
    }

 

    /// <summary>
    /// 实际执行的方法
    /// </summary>
    private void ExecuteMain()
    {
        //定义你自己要执行的Job
        ChinaPnrInterfaces.AutoSendRepaymentNotice();//定时发送短信提醒的方法
    }
    #region Timer 计时器定义
    /// <summary>
    /// 调用 callback 的时间间隔（以毫秒为单位）。指定 Timeout.Infinite 可以禁用定期终止。
    /// </summary>
    private static int Period = 1 * 60 * 60 * 1000;
    /// <summary>
    /// 调用 callback 之前延迟的时间量（以毫秒为单位）。指定 Timeout.Infinite 以防止计时器开始计时。指定零 (0) 以立即启动计时器。
    /// </summary>
    private static int dueTime = 3 * 1000;//三分钟后启动
    /// <summary>
    ///第几次执行
    /// </summary>
    private long Times = 0;
    /// <summary>
    /// 实例化一个对象
    /// </summary>
    private static readonly WebTimer_AutoRepayment _WebTimerTask = null;
    private Timer WebTimerObj = null;
    /// <summary>
    /// 是否正在执行中
    /// </summary>
    private int _IsRunning;
    /// <summary>
    /// 开始
    /// </summary>
    public void Start()
    {
        if (WebTimerObj == null)
        {
            DateTime now = DateTime.Now;
            int minutes = now.Minute;
            if (minutes >= 55)
            {
                dueTime = 0;//立即启动
            }
            else
            {
                dueTime = (55 - minutes) * 60 * 1000;//到某个时间点的55分钟启动
            }
            WebTimerObj = new Timer(new TimerCallback(WebTimer_Callback), null, dueTime, Period);
        }
    }
    /// <summary>
    /// WebTimer的主函数
    /// </summary>
    /// <param name="sender"></param>
    private void WebTimer_Callback(object sender)
    {
        try
        {
            if (Interlocked.Exchange(ref _IsRunning, 1) == 0)
            {
                ExecuteMain();
                Times++;
                Times = (Times % 100000);
            }
        }
        catch
        {
        }
        finally
        {
            Interlocked.Exchange(ref _IsRunning, 0);
        }
    }
    /// <summary>
    /// 停止
    /// </summary>
    public void Stop()
    {
        if (WebTimerObj != null)
        {
            WebTimerObj.Dispose();
            WebTimerObj = null;
        }
    }
    #endregion
}

 void Application_Start(object sender, EventArgs e)
    {
        //在应用程序启动时运行的代码
        WebTimer_AutoRepayment.Instance().Start(); //
    }

    void Application_End(object sender, EventArgs e)
    {
        //在应用程序关闭时运行的代码
        WebTimer_AutoRepayment.Instance().Stop();//
    }