Multiple Timers on Windows Service Not Firing Correctly

Question

I have inherited a Windows service to enhance at my company. Currently, the service prints a report daily of specific records in a database at a designated start time. I am adding a condition to set a second start time to run the same report omitting specific records. The problem I am running into is that I set the two separate start times (generally about 15 minutes apart), and it appears to be skipping over the first start time and only running the second one if the report files already exist.

    public partial class Service1 : ServiceBase
{
    Timer t1;
    Timer t2;
    bool Condition;

    public Service1()
    {
        InitializeComponent();
    }
    protected override void OnStart(string[] args)
    {
        t1 = new Timer();
        t1.Interval = (1000 * 60 * 3); // 3 minutes...
        t1.Elapsed += new ElapsedEventHandler(t1_Elapsed);
        t1.AutoReset = true;
        t1.Enabled = true;

        if (Condition) //Condition is an option in the configuration to determine if this timer should even start
        {
            t2 = new Timer();
            t2.Interval = (1000 * 60 * 3); // 3 minutes...
            t2.Elapsed += new ElapsedEventHandler(t2_Elapsed);
            t2.AutoReset = true;
            t2.Enabled = true;
        }
    }
    private void t1_Elapsed(object sender, ElapsedEventArgs e)
    {
        if (File.Exists("FileName1"))
        {
            string CurrentTime = DateTime.Now.ToShortDateString();

            if (CurrentTime == ConfigurationManager.AppSettings["StartTime"].ToString())
            {
                //Print Report
            }
        }
        else
        {
            //Print Report
        }
    }
    private void t2_Elapsed(object sender, ElapsedEventArgs e)
    {
        if (File.Exists("FileName2"))
        {
            string CurrentTime2 = DateTime.Now.ToShortDateString();

            if (CurrentTime2 == ConfigurationManager.AppSettings["StartTime2"].ToString())
            {
                //Print Report 2
            }
        }
        else
        {
            //Print Report 2
        }
    }        
    protected override void OnStop()
    {
        t1.Enabled = false;
        t2.Enabled = false;
    }
}

I can't figure out why this first one is getting skipped. Both will check if the file exists and print it if it doesn't. The next time it runs, the second report will print on it's scheduled time, but the first one gets skipped. I can't seem to figure out what I'm missing.

Why are you using two timers for this? Break the tasks into separate methods and call the methods from a single timer elapsed event and check your condition in the timer elapsed event. — JamieSee, Mar 30 '12 at 20:30
Side note, you should be using [scheduled tasks](http://stackoverflow.com/questions/7394806/creating-scheduled-tasks) for this. Service + timer = design smell. By doing this, you'd avoid most of the issue you're having. Also, the way you're comparing times seems super bugalicious. Your problem may lie within there. Hard to tell without seeing StartTime and StartTime2 as they actually are in your config file. — , Mar 30 '12 at 20:30
I originally had it as two separate methods on one timer, but I was having some sort of different issue that, unfortunately, I can't remember what it was. I have since made some other changes to this so changing it back may work. — LDWisdom, Mar 30 '12 at 20:46
@Will I had mentioned to someone that everyone suggested this should be a scheduled task, but there was an issue with credentials that someone else didn't want to deal with. However, I agree with you that this would be better suited to go that route. — LDWisdom, Mar 30 '12 at 20:48
Try out wrapping code in the elapsed_handlers by try/catch and log error, perhaps some exception raised whilst first entrance? — sll, Mar 30 '12 at 20:56
Check whether ConfigurationManager.AppSettings["StartTime"].ToString() is returning the exact value store din app.config or you have speel mistake in "StartTime" (should be "StartTime1" — Romil Kumar Jain, Apr 26 '12 at 09:27

score 2 · Answer 1 · edited May 23 '17 at 12:00

Is there any chance that you are using the wrong timer? I remember there were about 2 or 3 types of timers in .Net:

System.Timers.Timer

System.Thread.Timer

System.Windows.Forms.Timer

I believe in windows service you should use one of the first two, more likely System.Timers.Timer as it provides thread safetiness via the SynchronizationObject property: System.Timers.Timer vs System.Threading.Timer

Multiple Timers on Windows Service Not Firing Correctly

1 Answers1