Async Task.WhenAll with timeout

Question

Is there a way in the new async dotnet 4.5 library to set a timeout on the Task.WhenAll method. I want to fetch several sources and stop after say 5 seconds and

Answer 1

In addition to timeout, I also check the cancellation which is useful if you are building a web app.

public static async Task WhenAll(
    IEnumerable tasks, 
    int millisecondsTimeOut,
    CancellationToken cancellationToken)
{
    using(Task timeoutTask = Task.Delay(millisecondsTimeOut))
    using(Task cancellationMonitorTask = Task.Delay(-1, cancellationToken))
    {
        Task completedTask = await Task.WhenAny(
            Task.WhenAll(tasks), 
            timeoutTask, 
            cancellationMonitorTask
        );

        if (completedTask == timeoutTask)
        {
            throw new TimeoutException();
        }
        if (completedTask == cancellationMonitorTask)
        {
            throw new OperationCanceledException();
        }
        await completedTask;
    }
}