Can I add to, and yield from a ConcurrentQueue in parallel?

Question

I have a class that goes to get objects from a web service. My consumption of these objects is not order dependent so I issue my web requests in parallel and am adding the results to a ConcurrentQueue.

At the same time, as the requests are being made, we can process the responses.

So I would like to be able to iterate over the contents of the ConcurrentQueue while my items are being added to it.

How can I have one class fill up the queue and the other class empty it. It will almost certainly be emptied faster than it is filler, so I can't just enumerate it without having a yield because the collection will be empty and won't wait.

Answer 1

Use a BlockingCollection to wrap the ConcurrentQueue (the default backing store for a BlockingCollection is a ConcurrentQueue, so you don't even need to be explicit about it.

This allows you to write the consumer as:

foreach(var item in queue.GetConsumingEnumerable())
    Process(item);