C# Using a task to call a method continously until cancel token valid. RSS

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  ExceedingLif...

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  C# Using a task to call a method continously until cancel token valid.

  May 18, 2020 06:42 PM|ExceedingLife|LINK

  Hello every1, I have a C# app where I would like to call a method over and over until the user creates a cancel request on a thread in the background. I currently had it so I can call a action (a counter) and update the GUI each second but when I try to do this same thing with a method call it executes only once.

  // counter task action
  private void StartWork()
          {
              cancellationToken = new CancellationTokenSource();
  
              //task = Task.Factory.StartNew(async () =>
              Task.Run(async () => 
              {
                  while (true)
                  {
                      cancellationToken.Token.ThrowIfCancellationRequested();
  
                      await lblTest.Dispatcher.InvokeAsync(() => lblTest.Content = "Running2: " + counter);
                      counter++;
                      await Task.Delay(1000);
                  }
              }, cancellationToken.Token);
          }
  // Here is the method I want to call continously until canceled
  private async void HistoryTest()
          {
              cancellationToken = new CancellationTokenSource();
  
              task = Task.Factory.StartNew(async () =>
              {
                  while (true)
                  {
                      cancellationToken.Token.ThrowIfCancellationRequested();
  
                      await Client2.GetHistory();
                      await Task.Delay(2000);
                  }
              }, cancellationToken.Token);
             
          }
  public async Task GetHistory()
          {
              try
              {
                  var response = await Client.Service.GetDataAsync
                      (
                          ProductType.BtcUsd,
                          5,
                          1
                      );
              }
              catch(Exception)
              {
                  throw;
              }
          }

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  PaulTheSmith

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  1620 Points

  927 Posts

  Re: C# Using a task to call a method continously until cancel token valid.

  May 18, 2020 07:08 PM|PaulTheSmith|LINK

  ExceedingLife

  Here is the method I want to call continously until canceled

  What do you want to call continuously?

  a) HistoryTest - Where is the code that you currently have to call it

  b) GetHistory - it looks like it is called continuously

  You don't explicitly say it but this is an ASP.Net forum.  Are you trying to run this as part of a controller action?  If so, this is inherently unreliable.  Start your reading into the issue at https://haacked.com/archive/2011/10/16/the-dangers-of-implementing-recurring-background-tasks-in-asp-net.aspx/ and then move to a more up-to-date guide on how to achieve this at https://devblogs.microsoft.com/aspnet/queuebackgroundworkitem-to-reliably-schedule-and-run-background-processes-in-asp-net/