Periodically check to see if all threads have completed

Question

I have an multithreaded application and I want to be able to use a timer to periodically check to see if all threads have finished before starting a new one, ie:

var checkStatusTimer = new System.Threading.Timer(new TimerCallback(CheckThreads), null, 10000, 10000);

This is as far as I've come. What would need to go in the CheckThreads Method to check to see if they're done? I was thinking of something along the lines of a function that checks them like:

                foreach (Thread thread in Threads)
            {
                Thread t = thread;
                if (t.ThreadState != ThreadState.Stopped)
                    return false;
            }

Am I on the right track? is this the correct way to go about this? Or should I use a System.Timers.Timer instead? Also, the function form within I want to do this periodic check is static. Any help would be appreciated.

I suggest you add the tag [tag:C#] or whatever this is. – nwp Apr 29 '16 at 13:34 — nwp, Apr 29 '16 at 13:34

score 1 · Answer 1 · answered Apr 29 '16 at 13:31

1

Use Task instead of Thread. Then, you can create a combined task:

Task[] tasks = ...; //You provide this
Task combined = Task.WhenAll(tasks);

Now you can check for completion: combined.IsCompleted. You can also Wait and await that task.

Thread is a legacy API that is rarely a good idea to use.

answered Apr 29 '16 at 13:31

usr

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The application is running in .NET 3.5 which I believe doesn't support Tasks. – user609926 Apr 29 '16 at 14:05
@user609926 Use this nuget package to introduce Task to .net 3.5: https://www.nuget.org/packages/TaskParallelLibrary/ – Maarten Apr 29 '16 at 14:11

score 0 · Answer 2 · edited May 23 '17 at 12:31

0

@usr's task-based approach is best, but if you must rely on threads, then I suggest that as each thread is completes it invokes a method that removes the thread from your Threads collection. Then all you have to do in your timer callback is to check the count of the collection. Relying on ThreadState is not advisable.

edited May 23 '17 at 12:31

Community

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answered May 02 '16 at 21:47

Ed Power

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Periodically check to see if all threads have completed

2 Answers2