我需要添加什么才能使用“ using System.Timers;”？

Question

I work in xamarin forms and I need to use this assembly (using System.Timers;) but when I write it now it does not find Timers. Do I need to add a package?

I want to use it like this:

       var timer = new Timer (1000);
        timer.Elapsed += OnTimerElapsed;
        timer.Start ();

public static void OnTimerElapsed(object o, ElapsedEventArgs e)
{
 //code
 }

Answer 1

Do you want to use the Timer class in the PCL project? If so you will have to use Device.StartTimer

Device.StartTimer (new TimeSpan (0, 0, 60), () => {
    // do something every 60 seconds
    return true; // runs again, or false to stop
});

Answer 2

System.Timers is coming from the System.dll assembly. Here is the inforamation from msdn

Answer 3

Depending on the PCL profile, the Timer class won't be available. I use this snippet of code instead:

    delegate void TimerCallback(object state);

    sealed class Timer : CancellationTokenSource, IDisposable
    {
        internal Timer(TimerCallback callback, object state, int dueTime, int period)
        {
            if (dueTime <= 0)
                throw new ArgumentOutOfRangeException("dueTime", "Must be positive integer");

            if (period <= 0)
                throw new ArgumentOutOfRangeException("period", "Must be positive integer");

            Task.Delay(dueTime, Token).ContinueWith(async (t, s) =>
                {
                    var tuple = (Tuple<TimerCallback, object>)s;

                    while (true)
                    {
                        if (IsCancellationRequested)
                            break;
                        Task.Run(() => tuple.Item1(tuple.Item2));
                        await Task.Delay(period);
                    }

                }, Tuple.Create(callback, state), CancellationToken.None,
                TaskContinuationOptions.OnlyOnRanToCompletion,
                TaskScheduler.Default);
        }

        public new void Dispose()
        {
            Cancel();
        }
    }