Windows Service - How to make task run at several specific times?

Question

I have a windows service running. Within it the task runs currently at 7pm every day. What is the best way to have it run say fir example at 9.45am, 11.45am, 2pm, 3.45pm, 5p

Answer 1

In case you dont want to go for cron or quartz, write a function to find time interval between now and next run and reset the timer accordingly, call this function on service start and timeelapsed event. You may do something like this (code is not tested)

   System.Timers.Timer _timer;
    List timeToRun = new List();
    public void OnStart(string[] args)
    {

        string timeToRunStr = "20:45;20:46;20:47;20:48;20:49";
        var timeStrArray = timeToRunStr.Split(';');
        CultureInfo provider = CultureInfo.InvariantCulture;

        foreach (var strTime in timeStrArray)
        {
            timeToRun.Add(TimeSpan.ParseExact(strTime, "g", provider));
        }
        _timer = new System.Timers.Timer(60*100*1000);
        _timer.Elapsed += new System.Timers.ElapsedEventHandler(timer_Elapsed);
        ResetTimer();
    }


    void ResetTimer()
    {
        TimeSpan currentTime = DateTime.Now.TimeOfDay;
        TimeSpan? nextRunTime = null;
        foreach (TimeSpan runTime in timeToRun)
        {

            if (currentTime < runTime)
            {
                nextRunTime = runTime;
                break;
            }
        }
        if (!nextRunTime.HasValue)
        {
            nextRunTime = timeToRun[0].Add(new TimeSpan(24, 0, 0));
        }
        _timer.Interval = (nextRunTime.Value - currentTime).TotalMilliseconds;
        _timer.Enabled = true;

    }

    private void timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
    {
        _timer.Enabled = false;
        Console.WriteLine("Hello at " + DateTime.Now.ToString());
        ResetTimer();
    }