Demonstrates an InvalidOperationException when using BlockingCollection with ConcurrentBag as the underlying collection and calling TryTakeFromAny

BlockingCollection_ConcurrentBag_Issue.cs

using System;
using System.Collections.Concurrent;
using System.Threading;

namespace BlockingCollectionConcurrentBagException
{
    class Program
    {
        static void Main(string[] args)
        {
            // We only hold a reference to the outer BlockingCollection, not the inner ConcurrentBag
            var blockingCollection = new BlockingCollection<int>(new ConcurrentBag<int>());
            
            // Produce elements into the collection.
            var i = 0;
            var producerFunc = new WaitCallback[1];
            producerFunc[0] =
                state =>
                {
                    if (blockingCollection.Count == 0) blockingCollection.Add(i++);
                    else Thread.Yield();

                    ThreadPool.QueueUserWorkItem(producerFunc[0]);
                };
            ThreadPool.QueueUserWorkItem(producerFunc[0]);

            // Concurrently pull elements off the collection.
            var consumerFunc = new WaitCallback[1];
            consumerFunc[0] =
                ignored =>
                {
                    var success = false;
                    do
                    {
                        try
                        {
                            // THIS IS WHERE THE EXCEPTION OCCURS
                            success = blockingCollection.TryTake(out _);
                        }
                        catch (Exception exception)
                        {
                            Console.WriteLine(exception);
                        }
                    } while (success);

                    ThreadPool.QueueUserWorkItem(consumerFunc[0]);
                };

            // Start two competing consumers.
            ThreadPool.QueueUserWorkItem(consumerFunc[0]);
            ThreadPool.QueueUserWorkItem(consumerFunc[0]);

            Thread.Sleep(-1);
        }
    }
}