Currenly using the following code to wait for a collection of tasks to complete. However, I now have a situation where I want to be able to cancel/abort the WhenAll call, via a cancellation token preferably. How would I go about that?
Dim TaskCollection As New List(Of Tasks.Task)
For x As Integer = 1 To Threads
Dim NewTask As Tasks.Task = TaskHandler.Delegates(DelegateKey).Invoke(Me, Proxies, TotalParams).ContinueWith(Sub() ThreadFinished())
Await Tasks.Task.WhenAny(Tasks.Task.WhenAll(TaskCollection), XXX)
TaskCompletionSource<T> to create a task for some asynchronous condition that does not already have an asynchronous API. Use
CancellationToken.Register to hook the modern CancellationToken-based cancellation system into another cancellation system. Your solution just needs to combine these two.
I have a
CancellationToken.AsTask() extension method in my AsyncEx library, but you can write your own as such:
<System.Runtime.CompilerServices.Extension> _ Public Shared Function AsTask(cancellationToken As CancellationToken) As Task Dim tcs = New TaskCompletionSource(Of Object)() cancellationToken.Register(Function() tcs.TrySetCanceled(), useSynchronizationContext := False) Return tcs.Task End Function
Usage is as you expected:
Await Task.WhenAny(Task.WhenAll(taskCollection), cancellationToken.AsTask())