What must I do to make my methods awaitable?

Question

How can I roll my own async awaitable methods?

I see that writing an async method is easy as pie in some cases:

private async Task TestGeo() {     Geolocator geo = new Geolocator();     Geoposition pos = await geo.GetGeopositionAsync();     double dLat = pos.Coordinate.Latitude;     double dLong = pos.Coordinate.Latitude; } 

...but sadly also see that not just any method can be made async willy-nilly, though; to wit: this doesn't work:

private async Task TestAsyncAwait() {     int i = await TaSLs_Classes.TASLsUtils.GetZoomSettingForDistance(5); } 

...it stops me with the compile error, "Cannot await int"; a hint at design time similarly tells me, "type 'int' is not awaitable"

I also tried this with the same results:

    Task<int> i = await TaSLs_Classes.TASLsUtils.GetZoomSettingForDistance(5); 

What must I do to make my methods awaitable?

UPDATE

As Linebacker and S. Cleary indicated (any relation to that cat who used to be on KNBR?), this works:

int i = await Task.Run(() => TaSLs_Classes.TASLsUtils.GetZoomSettingForDistance(5)); 

...that is to say, it compiles -- but it never "moves."

At runtime, it tells me I should "await" the CALL to TestAsyncAwait(), but if I do that, it doesn't compile at all...

Answer 1

You only need to return an awaitable. Task/Task<TResult> is a common choice; Tasks can be created using Task.Run (to execute code on a background thread) or TaskCompletionSource<T> (to wrap an asynchronous event).

Read the Task-Based Asynchronous Pattern for more information.