CODEWITHSUNDEEP
c#
senzacionale
senzacionale

Reputation: 20936

Async Task how to return value back from a method

CancellationTokenSource cancellationTokenSource = new CancellationTokenSource();

Task tasks = PeriodicTaskFactory.Start(() => LongRunningOperation(), intervalInMilliseconds: 1000, synchronous: false, cancelToken: cancellationTokenSource.Token);

int taskId = Task.WaitAny(tasks);

and my LongRunningOperation

private String LongRunningOperation()
{
...
return proj.Name;
}

but the problem is how to get value from LongRunningOperation method back in Task. Method tasks.Results not exists. And I want to get back the value from each Task.

I get PeriodicTaskFactory class from here

Is there a Task based replacement for System.Threading.Timer?

Thank you

Upvotes: 1

Views: 6154

Answers (1)

dcastro
dcastro

Reputation: 68750

Task has no return value; Task<T> does.

You have to modify the PeriodicTaskFactory code to return Task<T> instead, and then create Task<string> objects. The method should also accept a Func<T> (has no arguments, returns T) instead of an Action, which has no return value.

public static Task<T> Start<T>(Func<T> func,
      int intervalInMilliseconds = Timeout.Infinite,
      int delayInMilliseconds = 0,
      int duration = Timeout.Infinite,
      int maxIterations = -1,
      bool synchronous = false,
      CancellationToken cancelToken = new CancellationToken(),
      TaskCreationOptions periodicTaskCreationOptions = TaskCreationOptions.None)
    {


Task<string> task = PeriodicTaskFactory.Start(LongRunningOperation, intervalInMilliseconds: 1000, synchronous: false, cancelToken: cancellationTokenSource.Token);

string result = task.Result;

Upvotes: 4

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