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    <p>I think you should implement your own <code>IProducerConsumerCollection&lt;T&gt;</code>. That's why it's an interface: so that you could easily make your own.</p> <p>You could do it using <code>Dictionary&lt;K,V&gt;</code> and <code>Queue&lt;T&gt;</code> to make sure receiving the data is fair, i.e. if you have just one device that produces data very fast, you won't send data just from this one.</p> <pre><code>public class DeviceDataQueue&lt;TDevice, TData&gt; : IProducerConsumerCollection&lt;Tuple&lt;TDevice, TData&gt;&gt; { private readonly object m_lockObject = new object(); private readonly Dictionary&lt;TDevice, TData&gt; m_data = new Dictionary&lt;TDevice, TData&gt;(); private readonly Queue&lt;TDevice&gt; m_queue = new Queue&lt;TDevice&gt;(); //some obviously implemented methods elided, just make sure they are thread-safe public int Count { get { return m_queue.Count; } } public object SyncRoot { get { return m_lockObject; } } public bool IsSynchronized { get { return true; } } public bool TryAdd(Tuple&lt;TDevice, TData&gt; item) { var device = item.Item1; var data = item.Item2; lock (m_lockObject) { if (!m_data.ContainsKey(device)) m_queue.Enqueue(device); m_data[device] = data; } return true; } public bool TryTake(out Tuple&lt;TDevice, TData&gt; item) { lock (m_lockObject) { if (m_queue.Count == 0) { item = null; return false; } var device = m_queue.Dequeue(); var data = m_data[device]; m_data.Remove(device); item = Tuple.Create(device, data); return true; } } } </code></pre> <p>When used along these lines:</p> <pre><code>Queue = new BlockingCollection&lt;Tuple&lt;IDevice, Data&gt;&gt;( new DeviceDataQueue&lt;IDevice, Data&gt;()); Device1 = new Device(1, TimeSpan.FromSeconds(3), Queue); Device2 = new Device(2, TimeSpan.FromSeconds(5), Queue); while (true) { var tuple = Queue.Take(); var device = tuple.Item1; var data = tuple.Item2; Console.WriteLine("{0}: Device {1} produced data at {2}.", DateTime.Now, device.Id, data.Created); Thread.Sleep(TimeSpan.FromSeconds(2)); } </code></pre> <p>it produces the following output:</p> <pre><code>30.4.2011 20:40:43: Device 1 produced data at 30.4.2011 20:40:43. 30.4.2011 20:40:45: Device 2 produced data at 30.4.2011 20:40:44. 30.4.2011 20:40:47: Device 1 produced data at 30.4.2011 20:40:47. 30.4.2011 20:40:49: Device 2 produced data at 30.4.2011 20:40:49. 30.4.2011 20:40:51: Device 1 produced data at 30.4.2011 20:40:51. 30.4.2011 20:40:54: Device 2 produced data at 30.4.2011 20:40:54. </code></pre>
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    1. POWhat type of IProducerConsumerCollection<T> to use for my task?
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    1. POWhat type of IProducerConsumerCollection<T> to use for my task?
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    1. COThanks, i think that should work for me! However I'm still investigating if i can implement what i want using standard collections, probably ConcurrentDictionary or using some "trick" suggested by Victor Hurdugaci. Your suggestion should work, but probably we can do the same easier...
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    2. COafter all I think i only want to store "index" of the updated sensor. Actual sensor data is stored in one place and I access it by reference. So I need no-duplicates ConcurentQueue where I will store "integers" - sensor indexes. created separate thread for my new question http://stackoverflow.com/questions/5845241/how-to-create-no-duplicates-concurrentqueue
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    3. COWell, my solution does that. If you don't want to store any data for each device, you can use `HashSet<T>` instead of the `Dictionary`. Or you could check the `Queue` itself, but that would be slower (at least asymptotically, it may be fast enough for your needs).
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