I think the current behavior makes sense. If I create my own task scheduler, and start some task that starts other tasks, I probably want all the tasks to use the scheduler I created. I agree that it’s odd that sometimes starting a task from the UI thread uses the default scheduler and sometimes not. … Read more
The immediate problem Your immediate problem is that SynchronizationContext.Current is not automatically set for WPF. To set it you will need to do something like this in your TheUISync code when running under WPF: var context = new DispatcherSynchronizationContext( Application.Current.Dispatcher); SynchronizationContext.SetSynchronizationContext(context); UISync = context; A deeper problem SynchronizationContext is tied in with the COM+ support … Read more
The issue is fixed in .NET 4.5 RC (just tested it). So I assume it is a bug in .NET 4.0. Also, I’m guessing that these posts are referencing the same issue: How can SynchronizationContext.Current of the main thread become null in a Windows Forms application? http://social.msdn.microsoft.com/Forums/en-US/wcf/thread/629d5524-c8db-466f-bc27-0ced11b441ba That’s unfortunate. Now I have to consider workarounds. … Read more
Stephen Cleary has a really good series on this you can find here, I quoted the piece specific to your question: Most of the time, you don’t need to sync back to the “main” context. Most async methods will be designed with composition in mind: they await other operations, and each one represents an asynchronous … Read more
The word “capture” is too opaque, it sounds too much like that is something that the framework is supposed to. Misleading, since it normally does in a program that uses one of the default SynchronizationContext implementations. Like the one you get in a Winforms app. But when you write your own then the framework no … Read more