Concise way to await a canceled Task?

Question

I find myself writing code like this a lot:

try
{
    cancellationTokenSource.Cancel();
    await task.ConfigureAwait(false); // this is the task that was cancelled
}
catch(OperationCanceledException)
{
    // Cancellation expected and requested
}

Given that I requested the cancellation, it is expected and I'd really like the exception to be ignored. This seems like a common case.

Is there a more concise way to do this? Have I missed something about cancellation? It seems like there should be a task.CancellationExpected() method or something.

Answer 1

I don't think there is anything built-in, but you could capture your logic in extension methods (one for Task, one for Task<T>):

public static async Task IgnoreWhenCancelled(this Task task)
{
    try
    {
        await task.ConfigureAwait(false);
    }
    catch (OperationCanceledException)
    {
    }
}

public static async Task<T> IgnoreWhenCancelled<T>(this Task<T> task)
{
    try
    {
        return await task.ConfigureAwait(false);
    }
    catch (OperationCanceledException)
    {
        return default;
    }
}

Then you can write your code simpler:

await task.IgnoreWhenCancelled();

or

var result = await task.IgnoreWhenCancelled();

(You might still want to add .ConfigureAwait(false) depending on your synchronization needs.)