task-parallel-library

问题 I have some code of the following form: static async Task DoSomething(int n) { ... } static void RunThreads(int totalThreads, int throttle) { var tasks = new List<Task>(); for (var n = 0; n < totalThreads; n++) { var task = DoSomething(n); tasks.Add(task); } Task.WhenAll(tasks).Wait(); // all threads must complete } Trouble is, if I don't throttle the threads, things start falling apart. Now, I want to launch a maximum of throttle threads, and only start the new thread when an old one is

问题 Edit See the title "Problem" at the end within my question to crack this question down. Coming from nodejs where we could chain promises, in C# I'm seeing Async Tasks almost comparable. Here's my attempt. Edit - I can't mark my uber level caller methods as async as a dll based library is calling it Caller object public void DoSomething(MyRequest request) { Delegate.Job1(request) .ContinueWith(Delegate.Job2) .ContinueWith(Fault, TaskContinuationOptions.OnlyOnFaulted) .ContinueWith(Result); }

问题 Following is Async Cache and Database update using Transaction Scope. I cannot use TransactionScopeAsyncFlowOption.Enabled introduced in the v 4.5.1, since the Apache Ignite.Net Cache I am using doesn't support it. I have tried finding a workaround by capturing the current Synchronization Context and then explicitly using Synchronization Context Send method to complete the transaction, but this doesn't work as I still get an error Transaction scope must be disposed on same thread it was

问题 In Brief I have a Windows Service that executes several jobs as async Tasks in parallel. However, when the OnStop is called, it seems that these are all immediately terminated instead of being allowed to stop in a more gracious manner. In more detail Each job represents an iteration of work, so having completed its work the job then needs to run again. To accomplish this, I am writing a proof-of-concept Windows Service that: runs each job as an awaited async TPL Task (these are all I/O bound

问题 I'm reading up more about async here: http://msdn.microsoft.com/en-us/library/hh873173(v=vs.110).aspx Going through this example: Task<bool> [] recommendations = …; while(recommendations.Count > 0) { Task<bool> recommendation = await Task.WhenAny(recommendations); try { if (await recommendation) BuyStock(symbol); break; } catch(WebException exc) { recommendations.Remove(recommendation); } } I wonder, if I'm already performing await on Task.WhenAny why do I need to await again inside of the

问题 I am starting a task with the following code: var token = tokenSource.Token; var taskWithToken = new Task(() => new ProcessMyCommand(_unitOfWork, ..., batchRunId, token).Execute(), token); In my continue with, I need to know the batchRunId and possibly some other variables listed in the ... , however, it doesn't apepar that this is possible??? taskWithToken.ContinueWith(task => { if (!task.IsCanceled) return; //TODO: make sure no more subsequent runs happen //TODO: sync with source data } );

问题 I am develop a Dataflow pipeline which reads a collection of files and, for each line in each file, performs a series of Dataflow blocks. After all steps have completed for each line in a file, I am wanting to execute further blocks on the file itself, but I don't know how this is possible. It is straightforward to split processing via a TransformManyBlock , but how can one then consolidate? I am used to Apache Camel's Splitter and Aggregator functionality - or there a fundamental disconnect

问题 Given : A list of ids of emails What I'm doing : With the BatchBlock group ids and call a Transformblock for each block the simplified transformblock looks like this: var readBatch = new TransformBlock<List<int>, IEnumerable<Email>>(idList => { List<Email> mails = new List<Email>(); foreach(var id in idList) { mails.Add(new Email(id)); } return mails; }); Now my next TransformBlock is defined like this TransformBlock<Email,EMail> filterStep; What I search : So I need a block which allows me

问题 I am trying to update my toolset with the new tools offered by C# 8, and one method that seems particularly useful is a version of Task.WhenAll that returns an IAsyncEnumerable. This method should stream the task results as soon as they become available, so naming it WhenAll doesn't make much sense. WhenEach sounds more appropriate. The signature of the method is: public static IAsyncEnumerable<TResult> WhenEach<TResult>(Task<TResult>[] tasks); This method could be used like this: var tasks =

问题 Why does task await forever?: var task = Observable .FromEventPattern<MessageResponseEventArgs>(communicator, "PushMessageRecieved") .Where(i => i.EventArgs.GetRequestFromReceivedMessage().Name == requestName) .Select(i => i.EventArgs) .RunAsync(System.Threading.CancellationToken.None) .ToTask(); task.Wait(); I know "PushMessageRecieved" is fired; I can set a break point on the Select lambda and hit it. But task.Wait() never moves. Better Update: FirstAsync() is what I am looking for: public