How to check if Thread finished execution

Question

I have following problem   I want to check  C   if a thread has finished execution  i e  if the thread method has returned  What I do now is call Thread Join 1   but this gives a 1 ms delay  Is there any way to simply check if a thread has finished  Inspecting Thread ThreadState just seems too cumbersome

User · Accepted Answer

Use the Thread IsAlive flag  This is to give the thread status

User · Answer

Use Thread Join TimeSpan Zero   It will not block the caller and returns a value indicating whether the thread has completed its work  By the way  that is the standard way of testing all WaitHandle classes as well

User · Answer

If you don t want to block the current thread by waiting checking for the other running thread completion  you can implement callback method like this   Action onCompleted        gt             On complete action     var thread   new Thread         gt          try                Do your work           finally             onCompleted                thread Start      If you are dealing with controls that doesn t support cross-thread operation  then you have to invoke the callback method  this Invoke onCompleted

User · Answer

I use IsAlive extensively  unless I want to block the current execution  of the calling thread   in which case I just call Join   without a parameter   Now  be aware that IsAlive may return false if the target thread has not actually started execution yet for any reason   Carlos Merighe

User · Answer

It depends on how you want to use it  Using a Join is one way  Another way of doing it is let the thread notify the caller of the thread by using an event  For instance when you have your graphical user interface  GUI  thread that calls a process which runs for a while and needs to update the GUI when it finishes  you can use the event to do this  This website gives you an idea about how to work with events   http   msdn microsoft com en-us library aa645739 28VS 71 29 aspx  Remember that it will result in cross-threading operations and in case you want to update the GUI from another thread  you will have to use the Invoke method of the control which you want to update

User · Answer

For a thread you have the myThread IsAlive property  It is false if the thread method returned or the thread was aborted

User · Answer

Take a look at BackgroundWorker Class  with the OnRunWorkerCompleted you can do it

User · Answer

You could fire an event from your thread when it finishes and subscribe to that   Alternatively you can call Thread Join   without any arguments      Blocks the calling thread until a thread terminates  while continuing to perform standard COM and SendMessage pumping    Thread Join 1  will      Blocks the calling thread until a thread terminates or the specified time elapses  while continuing to perform standard COM and SendMessage pumping    In this case the specified time is 1 millisecond

[c#] How to check if Thread finished execution

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