process list items in different threads

Question

At the moment I have List of Job objects that are queued to be processed sequentially shown in the code bellow.

   List<Job> jobList = jobQueue.GetJobsWithStatus(Status.New);
   foreach (Job job in jobList)
   {               
        job.Process();
   }

I am interested in running several Jobs at the same time in a limited number of threads (lets say 5 threads).

What is the best way to do this in c#?

Additional Notes:

• A Job object does not share resources with other jobs.
• Each Job takes about 10 seconds to process.
• Each job could connect to different resources.

Update: I have used a Semaphore because I could not limit the amount of active threads with a ThreadPool.

Answer 1

You will want to look into thread pools (for the simple answer). There is even a ThreadPool class in C# and it is quite easy to set up with great examples in the msdn library.

Answer 2

If you meant to use Threading, simple coding:

private static void TransferThread(ThreadStart tstart)
        {
            Thread thread = new Thread(tstart);
            thread.IsBackground = true;
            thread.Start();
}

Or you can you ThreadPool. This allows you to use any available thread and return it back to the pool after you're done.

Answer 3

If you're feeling adventurous you can use C# 4.0 and the Task Parallel Library:

Parallel.ForEach(jobList, curJob => {
  curJob.Process()
});

Answer 4

ThreadPool.QueueUserWorkItem()

This will queue a method for execution. It will execute when a thread pool thread is available.

Answer 5

I would give the .NET ThreadPool a try.