cancellationtokensource

问题 What I need to do is be able to cancel a task that is running async. I have been searching and cannot seem to wrap my head around it. I just cant seem to discern how it would be implemented into my current setup. Here is my code that fires my task off. Any help on where or how to implement a cancellation token would be greatly appreciated. private async void startThread() { //do ui stuff before starting ProgressLabel.Text = String.Format("0 / {0} Runs Completed", index.Count()); ProgressBar

问题 How to handle case, where user might hit the button, which invokes long running async operation, multiple time. My idea was first check if the async operation is running, cancel it and fire it again. So far I have tried to build this kind of functionality using CancellationTokenSource, but it is not working as expected. Some times there is two async operations running, so the "old" async oprations is not cancelled yet when I start new one and this mixes up the resul handling. Any suggestions

问题 After reading pretty much every question on Stack Overflow and Microsoft's documentation about NetworkStream, I dont understand what is wrong with my code. The problem I see is that my method GetDataAsync() hangs very often. I call this method from Init Method like so: public MyView(string id) { InitializeComponent(); MyViewModel myViewModel = session.Resolve<MyViewModel>(); //Autofac myiewModel.Init(id); BindingContext = myViewModel; } Above, my View does its initialization, then resolves

问题 I try to code a simple async write with timeout as below and expect the function to throw a TaskCanceledException given a very large buffer and small waitTime. However, this does not happen. WriteAsync will block for many seconds until the write completes. What am I missing? public async void WriteWithTimeout(Stream os, byte[] buf, int waitMs) { CancellationTokenSource tokenSource = new CancellationTokenSource(waitMs); // cancel after waitMs milliseconds. await os.WriteAsync(buf, 0, buf

问题 I'm using this code snippet to do an async query with a cancellation token: var _client = new HttpClient( /* some setthngs */ ); _client.GetAsync(someUrl, cancellationToken).ContinueWith(gettingTask => { cancellationToken.ThrowIfCancellationRequested(); SomeStuffToDO(); }, TaskScheduler.FromCurrentSynchronizationContext()); }, TaskScheduler.FromCurrentSynchronizationContext()); But, when operation get cancelled, cancellationToken.ThrowIfCancellationRequested(); throws an exception. I know

问题 This question is continuation from previous thread. store cancellation tokens in service fabric services Opened a new thread because answering this question would not be trivial. To summarize what has been discussed regarding cancel a job / task running in particular service in some partition of service fabric: Cancellation Token limitation: Cancellation token works within the service partition and that is the limitation in partition-wise storing the instances, probably the reason why

问题 Consider a Winforms application, where we have a button that generates some results. If the user presses the button a second time, it should cancel the first request to generate results and start a new one. We're using the below pattern, but we are unsure if some of the code is necessary to prevent a race condition (see the commented out lines). private CancellationTokenSource m_cts; private void generateResultsButton_Click(object sender, EventArgs e) { // Cancel the current generation of

问题 I see this code in front of me and I am suspicious: CancellationTokenSource _cts; public void Dispose(); { _cts.Cancel(); _cts.Dispose(); _task.Wait(); //wait for the task to be canceled!? } Is it safe to call _cts.Dispose() straight after cancel? Wouldn't that dispose of underlying resources of the CancellationTokenSource that are needed for the task being cancelled to successfully Wait on the CancellationToken, if it wanted to do so? 回答1: Is it safe to call _cts.Dispose() straight after

问题 I see this code in front of me and I am suspicious: CancellationTokenSource _cts; public void Dispose(); { _cts.Cancel(); _cts.Dispose(); _task.Wait(); //wait for the task to be canceled!? } Is it safe to call _cts.Dispose() straight after cancel? Wouldn't that dispose of underlying resources of the CancellationTokenSource that are needed for the task being cancelled to successfully Wait on the CancellationToken, if it wanted to do so? 回答1: Is it safe to call _cts.Dispose() straight after

问题 I have the following line of code used to read asynchronously from a NetworkStream: int bytesRead = await Task<int>.Factory.FromAsync(this.stream.BeginRead, this.stream.EndRead, buffer, 0, buffer.Length, null); I'd like to make it support cancellation. I see that I can cancel tasks using a CancellationTokenSource, however I don't see any way I can pass it to TaskFactory.FromAsync(). Is it possible to make a FromAsync()-constructed task support cancellation? Edit: I want to cancel a task that