// ------------------------------------------------------ // // Private Methods // // ------------------------------------------------------ #region Private Methods // Infinite loop. Wait for queue items to be processed. private void WaitForWork() { SafeWaitHandle handle = _ev.SafeWaitHandle; NativeMethods.MSG msg = new NativeMethods.MSG(); while (true) { try { // pump any messages while (UnsafeNativeMethods.PeekMessage(ref msg, IntPtr.Zero, 0, 0, NativeMethods.PM_REMOVE)) { if (msg.message == NativeMethods.WM_QUIT) { break; } Misc.DispatchMessage(ref msg); } // do any work items in the queue // It's possible items could be enqueued between when we check for the count // and dequeue but the event is set then and we'll come back into DrainQueue. // (note: don't use a for loop here because as the counter is incremented // Count is decremented and we'll only process half the queue) while (_q.Count > 0) { // pull an item off the queue, process, then clear it QueueItem item = (QueueItem)_q.Dequeue(); item.Process(); } int result = Misc.MsgWaitForMultipleObjects(handle, false, NativeMethods.INFINITE, NativeMethods.QS_ALLINPUT); if (result == NativeMethods.WAIT_FAILED || result == NativeMethods.WAIT_TIMEOUT) { Debug.Assert(false, "MsgWaitForMultipleObjects failed while WaitForWork"); break; } } catch (Exception e) { if (Misc.IsCriticalException(e)) { throw; } // Might happen when if the hwnd goes away between the peek and the dispatch } // } }