Difference between those two methods returning Task

Question

What's the Semantic difference between those two methods?

    public Task DoSomething()
    {
        return Task.Run(() => MyFunction());
    }

    public async Task DoSomethingAsync()
    {
        await Task.Run(() => MyFunction());
    }

Is there something I should think to choose between one or the other?

Is this a library/framework or an application built on a specific framework — Callum Linington, Jul 26 '16 at 10:52
There's big a difference in exception propagation and synchronization context handling, check [this](http://stackoverflow.com/q/21033150/1768303). — noseratio, Jul 27 '16 at 01:58

score 7 · Accepted Answer · answered Jul 26 '16 at 10:54

The actual difference is this:

The first method will call Task.Run and return the resulting task
The second method will be transformed into an async state machine that will call Task.Run, then queue up a continuation that when this task completes, will continue executing your method

In terms of "which one should I choose", here's the general guideline I use:

If all your method is going to do in relation to tasks is to return them then do not use async/await
If, instead, you need to "wait for" a task to complete, then do more stuff, then use async/await.

I am sure there are exceptions to this but I have yet to find any.

So of those two methods, pick the first.

@EhsanSajjad, yes it is better... http://stackoverflow.com/documentation/c%23/26/keywords/5993/await#t=201607261114381411264 — David Pine, Jul 26 '16 at 11:15

Difference between those two methods returning Task

1 Answers1