what's the proper way to use a ThreadPool?

Question

If my understanding of the way the ThreadPool works is correct, one of its purposes is to limit the number of worker threads within a process that can be created at a given

Answer 1

But my understanding of the way a ThreadPool works cannot be correct, because if it were correct the code below would print only the numbers 0-4, rather than 0-29.

Yes your assumption is very much correct.

Since u have queued 30 jobs in a ThreadPool and the Jobs will sleep for InfiniteTime, they will never finish, the ThreadPool class will wait for a certain interval to create new thread, but will not exceed the max number of threads.

NOTE

Console.Read() is keeping your Background thread alive.

Articles

• How to use a ThreadPool
  
• Working with ThreadPool

From MSDN

Many applications create threads that spend a great deal of time in the sleeping state, waiting for an event to occur. Other threads might enter a sleeping state only to be awakened periodically to poll for a change or update status information. Thread pooling enables you to use threads more efficiently by providing your application with a pool of worker threads that are managed by the system. One thread monitors the status of several wait operations queued to the thread pool. When a wait operation completes, a worker thread from the thread pool executes the corresponding callback function.

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When all thread pool threads have been assigned to tasks, the thread pool does not immediately begin creating new idle threads. To avoid unnecessarily allocating stack space for threads, it creates new idle threads at intervals. The interval is currently half a second, although it could change in future versions of the .NET Framework.

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The threads in the managed thread pool are background threads. That is, their IsBackground properties are true. This means that a ThreadPool thread will not keep an application running after all foreground threads have exited.