How to properly cancel parallel asynchronous IO Task by Escape key?
c#,async-await,task-parallel-library,.net-4.5,cancellation-token
First off, don't use async void. I'm not sure why the MSDN example encourages bad practice, but still, don't do that. Using async void means you're method is "fire and forget", it can't be asynchronously waited, and any exception that happens inside it will be thrown on a thread-pool thread....
CancellationTokenSource not behaving as expected
c#,.net,multithreading,task-parallel-library,cancellation-token
Let's start with a few facts: When you pass a CancellationToken as a parameter for Task.Run it only has an effect if it's cancelled before the task started running. If the task is already running it will not be canceled. To get a task canceled after it has started running,...
Can i cancel StreamReader.ReadLineAsync with a CancellationToken?
c#,.net,asynchronous,cancellation-token
You can't cancel the operation unless it's cancellable. You can use the WithCancellation ReadLineAsync extension method to have your code flow behave as if it was cancelled, but the underlying would still run: public static Task<T> WithCancellation<T>(this Task<T> task, CancellationToken cancellationToken) { return task.IsCompleted // fast-path optimization ? task :...
Why is the task is not cancelled when I call CancellationTokenSource's Cancel method in async method?
c#,asynchronous,task,cancellationtokensource,cancellation-token
Cancellation in .Net is cooperative. That means that the one holding the CancellationTokenSource signals cancellation and the one holding the CancellationToken needs to check whether cancellation was signaled (either by polling the CancellationToken or by registering a delegate to run when it is signaled). In your Task.Run you use the...
How to run code when a CancellationToken is cancelled?
You can register an Action to be invoked when the token is canceled: token.Register(() => { /*...*/ }); ...
What is the proper way to delay with cancellation support inside of a task execution delegate?
c#,.net,task-parallel-library,cancellationtokensource,cancellation-token
So, a task is considered canceled when an OperationCanceledException is thrown and uncaught inside it and its associated CancellationToken is canceled. In your case the exception being thrown is AggregateException that contains a TaskCanceledException (which is an OperationCanceledException) instead of the TaskCanceledException directly. There's a simple way to fix that....
How to wait for Cancellation Token Register method within a PLINQ
c#,.net-4.0,task,plinq,cancellation-token
Well, you can easily wait for all these using a CountdownEvent. You set it's size at the start, signal it after every library.Clean() and wait for it to reach 0 using Wait(): private CountdownEvent _countdownEvent; public void Cancel() { cs.Cancel(); _countdownEvent.Wait(); // Update UI } public void StartProcessing() { try...
How can I cancel a Task without LOOP
c#,async-await,cancellation-token
I'm assuming token is a CancellationToken? You wouldn't need a loop, instead take a look at CancellationToken.ThrowIfCancellationRequested. By calling this, the CancellationToken class will check if it has been canceled, and kill the task by throwing an exception. Your task code would then turn into something like: using System.Threading.Tasks; Task.Factory.StartNew(()=>...
Is CancellationTokenSource mandatory when CancellationToken is requested?
c#,.net,cancellationtokensource,cancellation-token
No. You can't cancel a CancellationToken directly without invoking CancealltionTokenSource.Cancel which means that using only the Token is pretty useless (it will never be signaled, you could just use CancellationToken.None instead) Cancellation works where one side has the means to notify cancellation (CancellationTokenSource) and the other side needs to observe...