I have following code:

private void ProcessQueue()
{
    foreach (MessageQueueItem item in GetNextQueuedItem())
        PerformAction(item);
}

private IEnumerable<MessageQueueItem> GetNextQueuedItem()
{
    if (_messageQueue.Count > 0)
        yield return _messageQueue.Dequeue();
}

Initially there is one item in the queue as ProcessQueue is called. During PerformAction, I would add more items to _messageQueue. However, the foreach loop quits after the initial item and does not see the subsequent items added.

I sense that somehow the initial state of the queue is being captured by yield.

Can someone explain what is happening and give a solution?