How to wait on WaitHandle without message pumping?
WaitForSingleObject or WaitForMultipleObjects are non-pumping waits; use p/invoke.
[DllImport("kernel32", SetLastError=true, ExactSpelling=true)]public static extern Int32 WaitForSingleObject(SafeWaitHandle handle, Int32 milliseconds);-Oisin
Apparently this was a change introduced in Microsoft Vista: CoWaitForMultipleHandles now dispatches WM_PAINT messages.
A workaround is to use Microsoft's Application Compatibility Toolkit to set the DisableNewWMPAINTDispatchInOLE flag for your application.
If you're in a WPF app where the Dispatcher is the one running the message pumps during managed waits, the simplest way to disable the message pump during your wait is via Dispatcher.DisableProcessing:
// The Dispose() method is called at the end of the using statement. // Calling Dispose on the DispatcherProcessingDisabled structure, // which is returned from the call to DisableProcessing, will // re-enable Dispatcher processing. using (Dispatcher.CurrentDispatcher.DisableProcessing()){ // Do work while the dispatcher processing is disabled. Thread.Sleep(2000);}