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URGENT: Problem with Multi Threading

Posted on 2003-11-30
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Last Modified: 2010-05-19
I am running the following code:

//this.BeginInvoke(m_DelegateReload, null);
ThreadStart start = new ThreadStart(ReloadDataHelper);
Thread t = new Thread(start);
t.IsBackground = true;
t.Start();

But, it is not dying when the calling thread, the main GUI, exits.  I am calling Application.Exit() and then getting an error from the ReloadDataHelper because it is trying to populate a list view that does not exist.  can someone help?  
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Question by:jjacksn
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13 Comments
 
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Expert Comment

by:Balder1978
ID: 9847097
I dont understand exactly, but why can't you use:

ThreadStart start = new ThreadStart(ReloadDataHelper);
start.IsBackground = true;
start.Start();
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Expert Comment

by:Balder1978
ID: 9847104
Sorry, didn't read it all...
private Thread t;

t = new Thread(new ThreadStart(ReloadDataHelper));
t.IsBackground = true;
t.Start();

in the Form_Closing event:
if (t != null && t.IsAlive) t.Abort();

Hope this helps.
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Expert Comment

by:smegghead
ID: 9847137
Are there any other threads that are foreground which might still be running ?? your original code looks like it should work in the way you want

from MSDN.

"a background thread will not keep the managed execution environment alive. Once all foreground threads have been stopped in a managed process (where the .exe file is a managed assembly), the system stops all background threads and shuts down."

Is the exe a managed assembly??

Smg.
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Author Comment

by:jjacksn
ID: 9847686
I don't think so.  Every thread I start in my program is run as a background thread.  There are multiple background threads running...

These is a different question, but maybe you can help here.  Whenever I go to file->exit my application closes.  But sometime, the X button doesn't work.  Why would it sometimes not work to close the application?  
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Expert Comment

by:Balder1978
ID: 9848456
Because some theard is still running,  At least that is what happend to me...
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Author Comment

by:jjacksn
ID: 9848711
is there a way to force the X button to Call Application.Exit()?  How can I add a handler to it.  Adding to close or closing does not work, obviously, since the form is not closing when that button is clicked.
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Expert Comment

by:smegghead
ID: 9849571
I had this problem a while back, and it was due to a timer on the form which was still active.
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Author Comment

by:jjacksn
ID: 9851231
I do have background threads running, I would just like them to die (I"m mean).  So how can I add a handler to the X button?
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Expert Comment

by:Balder1978
ID: 9851319
The forms Closing event!
Check if the threads are running or not with Thread.IsAlive, so if it is alive, then do a Thread.Abort() to terminate the thread
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Expert Comment

by:AvonWyss
ID: 10024867
Your threads will die. The problem seems more to be that the thread is trying to access some GUI component (which a thread should not do anyways) and this leads to an exception...
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Accepted Solution

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jrberg earned 2000 total points
ID: 10110539
Create a global ArrayList in your main class and every time you create a thread store a reference to it in the ArrayList.  Then inside of your protected override void dispose() method loop the ArrayList and kill the threads if they are still active.

Hope this helps,
Jerry

1) ArrayList threadArrayList; // Create this globally

2) threadArrayList.Add( thread ); // Do this every time you create a thread

3) Do this in your dispose method
for( int i=0; i<threadArrayList.Count; i++ )
{
  if(((Thread)threadArrayList[i]).IsAlive)
  {
     ((Thread)threadArrayList[i]).Abort();  
  }
}

Hope this idea gives you what you need,
Jerry
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Expert Comment

by:AvonWyss
ID: 10122608
Note: you'd need to synchronize the ArrayList or you may get strange results...
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Expert Comment

by:jrberg
ID: 10193559
I've never had any problems.
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