When to use TaskEx.Run vs. TaskEx.RunEx

Question

I\'m trying to understand when to use TaskEx.Run. I have provided two code sample i wrote below that produce the same result. What i fail to see is why i would ta

Answer 1

Task.Run spawns a new thread in most scenarios as I understand it.

It's important to note that simply because you mark a method as async, and use awaiters, this does NOT (necessarily) mean that new threads are being created, completions are scheduled on the SAME thread of execution that they were called from in many cases.

The trick here has to do with the SchedulingContext. If it's set for a multithreaded apartment, then you're going to delegate completions to viable threads on the threadpool. If you're in a singlethreaded apartment as all WPF and WinForms UI code is, then it will return to the calling thread for completion allowing work to be done directly on the UI without visible thread marshalling in the code.