using System.Collections.Concurrent;

using System.Collections.Generic;

using System.Threading;

using System.Threading.Tasks;

​

public class Program

{

    // Note: This example does not run.

    public static void Main()

    {

        var tasks = new List<Task>();

        int maxThreads = 50, threadWaitTime = 3000;

        var token = new CancellationToken();

​

        // Using ConcurrentDictionary

        var bbrQueue = new ConcurrentQueue<string>();

        // Add items to ConcurrentDictionary via .Enqueue()

        // bbrQueue.Enqueue("foo");

        while (0 == 0 && !token.IsCancellationRequested)

        {

            string key;

            if (bbrQueue.TryDequeue(out key))

            {

                // Create task to work on dequeued item

                // tasks.Add(...);

            }

            else

            {

                // Wait for ConcurrentQueue to have more items added to it

                Thread.Sleep(threadWaitTime);

            }

​

            if (tasks.Count >= maxThreads)

            {

                // Clean up completed tasks

                Task.WaitAll(tasks.ToArray(), token);

                tasks.Clear();

            }

        }

        // Using BlockingCollection

        var bbrCollection = new BlockingCollection<string>();

        // Add items to BlockingCollection via .Add()

        // bbrCollection.Add("foo");

        foreach (var sku in bbrCollection.GetConsumingEnumerable(token))

        {

            // Create task to work on dequeued item

            // tasks.Add(...);

​

            if (tasks.Count >= maxThreads)

            {

                // Clean up completed tasks

                Task.WaitAll(tasks.ToArray(), token);

                tasks.Clear();

            }

        }

    }

}