Utilisez un Minuterie pour traiter le message et l'annulation automatique. Lorsque la tâche est terminée, appelez Dispose sur les temporisateurs afin qu'ils ne se déclenchent jamais. Voici un exemple ; changez taskDelay à 500, 1500, ou 2500 pour voir les différents cas :
using System;
using System.Threading;
using System.Threading.Tasks;
namespace ConsoleApplication1
{
class Program
{
private static Task CreateTaskWithTimeout(
int xDelay, int yDelay, int taskDelay)
{
var cts = new CancellationTokenSource();
var token = cts.Token;
var task = Task.Factory.StartNew(() =>
{
// Do some work, but fail if cancellation was requested
token.WaitHandle.WaitOne(taskDelay);
token.ThrowIfCancellationRequested();
Console.WriteLine("Task complete");
});
var messageTimer = new Timer(state =>
{
// Display message at first timeout
Console.WriteLine("X milliseconds elapsed");
}, null, xDelay, -1);
var cancelTimer = new Timer(state =>
{
// Display message and cancel task at second timeout
Console.WriteLine("Y milliseconds elapsed");
cts.Cancel();
}
, null, yDelay, -1);
task.ContinueWith(t =>
{
// Dispose the timers when the task completes
// This will prevent the message from being displayed
// if the task completes before the timeout
messageTimer.Dispose();
cancelTimer.Dispose();
});
return task;
}
static void Main(string[] args)
{
var task = CreateTaskWithTimeout(1000, 2000, 2500);
// The task has been started and will display a message after
// one timeout and then cancel itself after the second
// You can add continuations to the task
// or wait for the result as needed
try
{
task.Wait();
Console.WriteLine("Done waiting for task");
}
catch (AggregateException ex)
{
Console.WriteLine("Error waiting for task:");
foreach (var e in ex.InnerExceptions)
{
Console.WriteLine(e);
}
}
}
}
}
En outre, le CTP asynchrone fournit une méthode TaskEx.Delay qui englobe les temporisateurs dans des tâches pour vous. Cela peut vous donner plus de contrôle pour faire des choses comme définir le TaskScheduler pour la continuation lorsque le timer se déclenche.
private static Task CreateTaskWithTimeout(
int xDelay, int yDelay, int taskDelay)
{
var cts = new CancellationTokenSource();
var token = cts.Token;
var task = Task.Factory.StartNew(() =>
{
// Do some work, but fail if cancellation was requested
token.WaitHandle.WaitOne(taskDelay);
token.ThrowIfCancellationRequested();
Console.WriteLine("Task complete");
});
var timerCts = new CancellationTokenSource();
var messageTask = TaskEx.Delay(xDelay, timerCts.Token);
messageTask.ContinueWith(t =>
{
// Display message at first timeout
Console.WriteLine("X milliseconds elapsed");
}, TaskContinuationOptions.OnlyOnRanToCompletion);
var cancelTask = TaskEx.Delay(yDelay, timerCts.Token);
cancelTask.ContinueWith(t =>
{
// Display message and cancel task at second timeout
Console.WriteLine("Y milliseconds elapsed");
cts.Cancel();
}, TaskContinuationOptions.OnlyOnRanToCompletion);
task.ContinueWith(t =>
{
timerCts.Cancel();
});
return task;
}
