Question

I have an application (.Net 3.5) which creates threads to write something to the database so that the GUI does not block. All created threads are added to a list, so that I can wait (Thread.Join) for each thread when the application is closed (maybe not all threads are finished when the application is closed, so the app must wait for them).
Because of the list I get some serious problems if there are too many threads created (OutOfMemoryException). I tried removing finished threads from the list, but somehow that didn’t work.
Are there better ways to manage a list of threads, so I can remove them once they are finished?

Edit: It seems that fixed it (called whenever a thread is added):


lock (m_threadLock)
{
m_threads.RemoveAll(x => x.ThreadState == ThreadState.Stopped);
}

Answer 1

You cannot keep on creating new threads while keeping a hold on the old ones, you’ll run out of memory.

I tried removing finished threads from the list, but somehow that didn’t work.

That is the right path, why didn’t it work?

1. Add code to your thread-methods to signal completion (maybe remove themselves from the list).
2. Look for a custom ThreadPool. There are several implementations published. You can use a simple one and control Background=false and other details.