5 useful extensions for Task<T> in .NET

[giscus[bot]]

5 useful extensions for Task in .NET

In this short blog post, I will show you 5 useful extensions for Task in .NET. We will build them as extension methods, so there are easy to use.
On top, I will show a small example of how to use them. So let's go!

https://steven-giesel.com/blogPost/d38e70b4-6f36-41ff-8011-b0b0d1f54f6e

[curia-damiano]

Very nice article, thank you!

Is there a reason why, in section 4, there are no ConfigureAwait(false) ?

[linkdotnet]

Hey - thanks @curia-damiano
And no there is no reason - I just forgot :D.
I will add this.

[MohammadHadi2031]

Can we use Task.WaitAsync instead of WithTimeout in section 4?

[linkdotnet]

Yes - since .NET 6 you can use WaitAsync. I will amend the post! Thanks

[curia-damiano]

In section 4, I think you can also do await task.ConfigureAwait(false); Btw really annoying, I know...

…

On Wed, Apr 12, 2023 at 7:32 AM Steven Giesel ***@***.***> wrote: Yes - since .NET 6 you can use WaitAsync. I will amend the post! Thanks — Reply to this email directly, view it on GitHub <#53 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AEN72MYVMUAIEWSRGHJ7DHLXAY5ADANCNFSM6AAAAAAW2HHGK4> . You are receiving this because you were mentioned.Message ID: ***@***.*** com>

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[rikbosch]

In case of section 2 (retry) wouldn't you want the Task continuing on the original context (if any)? Now, the first execution will run on within the original context, but the retries will be scheduled outside of the original context (somewhere in the threadpool).

In asp.net (core) you won't notice this as there is no synchronization context (https://blog.stephencleary.com/2017/03/aspnetcore-synchronization-context.html), but in a UI application or old-school asp.net this could cause issues.

[curia-damiano]

Correct, but usually it will be the caller that will re-enter the original context.
If there is a UI update inside the async call, there will be need of a Dispatcher.

i.e. the caller can't call an async method and do direct UI updates, assuming to be in the main thread - otherwise it wouldn't be an async method by definition

[molszews]

Re 4. in this implementation will the original (potentailly long running) Task be cancelled after specified timeout or not?

[linkdotnet]

This version doesn’t pass in a cancellation token. So it would still run. You could adopt it to use such a token

[slaneyrw]

section 4... be careful about using Task.Delay. Under the hood it sets up a Timer which will only be disposed on completion of the delay... whether or not you are still awaiting the result. If the delay is used in a loop, or relatively long lasting, you may end up using more resources than you would expect.

To my knowledge, there is no wait to dispose this internal timer if you no longer want to wait.

However there are no reasonable alternatives though.

[MohammadHadi2031]

In section 2. How about catching OperationCanceledException and prevent from retrying?

try
{
    ...
}
catch (OperationCanceledException)
{
    throw;
}
catch 
{
    ...
}

[linkdotnet]

Yes that would be a good edition! Well put

[msftgeek]

Great extensions!

But, I run into this when trying to build #4: (.NET 6)

https://learn.microsoft.com/en-us/dotnet/csharp/misc/cs1503?f1url=%3FappId%3Droslyn%26k%3Dk(CS1503)

Severity Code Description Project File Line Suppression State
Error CS1503 Argument 2: cannot convert from 'System.Runtime.CompilerServices.ConfiguredTaskAwaitable' to 'System.Threading.Tasks.Task' ACME.CommonLibrary C:\repos\ACME.CommonLibrary\ACME.CommonLibrary\Extensions\TaskExtensions.cs 54 Active

[linkdotnet]

Yeah that is my fault - I accidently added too many ConfigureAwaits ;). Fixed