Question

我使用xamarin表单，我需要使用这个程序集（使用System.Timers;）但是当我现在写它时它找不到Timers。我需要添加包吗？

我想这样用：

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

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

Answer 1

您想在PCL项目中使用Timer类吗？如果是这样，您将不得不使用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来自System.dll程序集。以下是来自msdn

的信息

Answer 3

根据PCL配置文件，Timer类不可用。我使用这段代码代替：

    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();
        }
    }

使用“使用System.Timers;”需要添加什么？

3 个答案: