System.Timers.Timer delay hangs application

Question

I have an issue with the System.Timers.Timer object. I use the timer object to perform a task at regular intervals. In the timer constructor I call the method doing the work ( DoTimeCheck() ), to ensure that the task is run once at startup also. The work (at regular intervals) is done in a BackgroundWorker.

I call the timer with this:

 UpdaterTimer ut = UpdaterTimer.UpdaterTimerInstance;

My problem is that I need to delay the first run of the task with 3 minutes(the one that runs at application startup). Subsequent runs (Elapsed event) should run without delay. I thought of doing this by calling

System.Threading.Thread.Sleep(TimeToDelayFirstRunInMiliseconds);

but this fails, because it also hangs the UI of the app (main thread) making it unusable. How can I delay the first run of DoTimeCheck() without hanging the UI? The code of the timer is below. If the issue is not presented in a clear manner please let me know and I will edit. Thank you in advance.

  public sealed class UpdaterTimer : Timer
{
    private static readonly UpdaterTimer _timer = new UpdaterTimer();
    public static UpdaterTimer UpdaterTimerInstance
    {
        get { return _timer; }
    }

    static UpdaterTimer()
    {
        _timer.AutoReset = true;
        _timer.Interval = Utils.TimeBetweenChecksInMiliseconds;
        _timer.Elapsed += new ElapsedEventHandler(_timer_Elapsed);
        _timer.Start();
        DoTimeCheck();

    }

    static void _timer_Elapsed(object sender, ElapsedEventArgs e)
    {
        DoTimeCheck();
    }

    private static void DoTimeCheck()
    {
        //... work here 
    }
}

Is that the entire class? (just curious about inheriting from Timer with all static methods) — Austin Salonen
– Austin Salonen, Commented Aug 12, 2011 at 14:26
thank you for your comment - that is the relevant entire class yes, apart from the code inside DoTimeCheck(). all the statics are supposed to ensure that only one timer is run - a singleton. Of course this may not be the best way of inheriting from System.Timers.Timer (i'm a newb), but it has worked so far. — Amc_rtty
– Amc_rtty, Commented Aug 12, 2011 at 14:40

Peter Kelly · Accepted Answer · 2011-08-12 14:45:09Z

4

One way of doing this would be to give the Timer Interval an initial value (e.g. 3 minutes). Then, in your Elapsed event handler, you could change the interval to your regular value which will be used from then on.

 _timer.Interval = Utils.InitialCheckInterval;

 static void _timer_Elapsed(object sender, ElapsedEventArgs e)
 {
     if (_timer.Interval == Utils.InitialCheckInterval)
     {
         _timer.Interval = Utils.RegularCheckInterval;
     }

     DoTimeCheck();
 }

edited Aug 12, 2011 at 14:45

answered Aug 12, 2011 at 14:24

Peter Kelly

14.5k7 gold badges57 silver badges64 bronze badges

Sign up to request clarification or add additional context in comments.

6 Comments

Chris Over a year ago

Do you not want to swap Utils.TimeBetween... with Utils.RegularInterval?

Peter Kelly Over a year ago

Don't think so - the timer will be set to initial value. Then the first time the Interval Elapses it will be changed to the regular interval.

Chris Over a year ago

I think you edited it between my and your comment and I'm suspecting you only saw my comment after the edit. But yes, it looks good now. :)

Peter Kelly Over a year ago

@Chris I did - but I didn't swap them, just made the names clearer. Think we were both thinking the same anyway.

Chris Over a year ago

@Peter Kelly: Yeah, we're on the same page so all is good. At least it shows that making the names clearer was worthwhile. ;-)

|

Kiril · Accepted Answer · 2011-08-12 14:24:54Z

1

It appears (although you've not shown that code) that you're calling Sleep(TimeToDelayFirstRunInMiliseconds); on the main/GUI thread, so that's what's causing your UI thread to hang. Instead, you should set your timer to be delayed by 3 minutes on the first run, then once it runs you change the timer again to run at the frequency you desire for all the subsequent runs.

answered Aug 12, 2011 at 14:24

Kiril

40.6k34 gold badges180 silver badges229 bronze badges

Comments

James Johnson · Accepted Answer · 2011-08-12 14:31:33Z

1

Your UI resides on the same thread, so when you put the thread to sleep, it will cause your UI to hang as well. You need to run the timer on a different thread.

answered Aug 12, 2011 at 14:31

James Johnson

46.1k8 gold badges75 silver badges111 bronze badges

2 Comments

Amc_rtty Over a year ago

thank you for your comment - I only use a BackgroundWorker to do the long work. Other than that, I stay away from multithreading because that is a thin ice for me, I do not have a good understanding of multithreading yet.

James Johnson Over a year ago

You're going to need it here. There are safe ways to do multithreading in .NET though, so don't be discouraged. Take a look at this link: msdn.microsoft.com/en-us/library/ms951089.aspx

Chris · Accepted Answer · 2011-08-12 14:55:36Z

1

You're already using timers fine it seems. Just use another one to do a three minute delay before you start up your other timer.

timer = new Timer();
timer.AutoReset = false;
timer.Interval = 3*60*1000;
timer.Elapsed += startOtherTimerMethod;
timer.Start();

Edit: I should note that this is much the same as Peter Kelly's answer except that his solution is more elegant since it uses just one timer, no extra methods and takes advantage of the fact that the timer is changeable between runs. If you liked this answer, you'll love his. ;-)

edited Aug 12, 2011 at 14:55

answered Aug 12, 2011 at 14:28

Chris

27.7k7 gold badges77 silver badges94 bronze badges

Comments

m.edmondson · Accepted Answer · 2011-08-12 14:23:28Z

0

Your UI needs a seperate thread, currently you are also sleeping the UI. Check this post.

answered Aug 12, 2011 at 14:23

m.edmondson

30.9k29 gold badges129 silver badges212 bronze badges

Comments

Luis Valencia · Accepted Answer · 2011-08-12 14:25:41Z

0

You should not use thread.sleep in this situation you should use the winforms control

BackgroundWorker which never locks the main UI. You can write your logic there.

example here: http://www.knowdotnet.com/articles/backgroundworker.html

answered Aug 12, 2011 at 14:25

Luis Valencia

34.3k99 gold badges317 silver badges534 bronze badges

1 Comment

Amc_rtty Over a year ago

thank you but i already use BackgroundWorker for the method that does all the work. I have already tried adding the sleep method inside the BackgroundWorker but : 1 - hanging of UI still happens and 2 - this means that the delay will happen on each timer.Elapsed() event, and I need to delay only the first run.

Yahia · Accepted Answer · 2011-08-12 14:40:38Z

0

Use a System.Threading.Timer - the constructor takes a parameter for the delay of the first run and an interval for the subsequent runs.

edited Aug 12, 2011 at 14:40

answered Aug 12, 2011 at 14:32

Yahia

70.5k9 gold badges117 silver badges147 bronze badges

Collectives™ on Stack Overflow

System.Timers.Timer delay hangs application

7 Answers 7

6 Comments

Comments

2 Comments

Comments

Comments

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

7 Answers 7

6 Comments

Comments

2 Comments

Comments

Comments

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related