Question

我正试图在每一分钟发射一个方法。

我正在使用下面的代码，但我注意到计时器可以提前几毫秒启动。

我该如何解决这个问题？

    public partial class Form1 : Form
    {

        DateTime RoundUpFuzzy(DateTime dt, TimeSpan d)
        {
            int n=1;
            if (dt.Millisecond > 900)
                n = 2;
            return new DateTime(((dt.Ticks + (d.Ticks*n) - 1) / d.Ticks) * d.Ticks);
        }

        public void HistMatch()
        {
            for (int i = 0; i < 10; i++)
            {
                var now = DateTime.UtcNow;
                var nextDT = RoundUpFuzzy(now, TimeSpan.FromMinutes(1));
                var waitTS = nextDT.Subtract(now);
                Console.WriteLine("Now: " + now.ToString("HH:mm:ss.fff") + " nextDT: " + nextDT.ToString("HH:mm:ss.fff")+" wait MS: " + waitTS.TotalMilliseconds);
                System.Threading.Thread.Sleep(waitTS);
            }
        }
}

输出：

Now: 09:12:16.308 nextDT: 09:13:00.000 waitMS: 43691.7256
Now: 09:12:59.999 nextDT: 09:14:00.000 waitMS: 60000.0952
Now: 09:13:59.990 nextDT: 09:15:00.000 waitMS: 60009.0949
Now: 09:14:59.992 nextDT: 09:16:00.000 waitMS: 60007.4955
Now: 09:15:59.993 nextDT: 09:17:00.000 waitMS: 60006.2285
Now: 09:16:59.996 nextDT: 09:18:00.000 waitMS: 60003.2285
Now: 09:17:59.996 nextDT: 09:19:00.000 waitMS: 60003.2285
Now: 09:18:59.996 nextDT: 09:20:00.000 waitMS: 60003.2285

编辑1 - 附加测试代码

这里我尝试3个版本，每分钟运行一个事件。只有第一个“Test_Sleep”是准确的。如何使用计时器获得相同的结果？

public partial class Form1 : Form
{
    System.Threading.Timer threadingTimer;
    System.Timers.Timer timersTimer;

    public Form1()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        Test_Sleep();
        Test_ThreadingTimer("");
        Test_TimersTimer("", null);
    }

    public void Test_TimersTimer(object o, System.Timers.ElapsedEventArgs e)
    {
        var now = DateTime.UtcNow;
        var nextDT = RoundUpFuzzy(now, TimeSpan.FromMinutes(1));
        var ms = nextDT.Subtract(now);
        Console.WriteLine("Now: " + now.ToString("HH:mm:ss.fff") + " nextDT: " + nextDT.ToString("HH:mm:ss.fff") + " waitMS: " + ms.TotalMilliseconds);
        timersTimer = new System.Timers.Timer();
        timersTimer.Interval = (int)ms.TotalMilliseconds;
        timersTimer.Elapsed += Test_TimersTimer;
        timersTimer.AutoReset = false;
        timersTimer.Enabled = true;
    }

    public void Test_ThreadingTimer(object o)
    {
        var now = DateTime.UtcNow;
        var nextDT = RoundUpFuzzy(now, TimeSpan.FromMinutes(1));
        var ms = nextDT.Subtract(now);
        Console.WriteLine("Now: " + now.ToString("HH:mm:ss.fff") + " nextDT: " + nextDT.ToString("HH:mm:ss.fff") + " waitMS: " + ms.TotalMilliseconds);
        threadingTimer = new System.Threading.Timer(new System.Threading.TimerCallback(Test_ThreadingTimer), null, ms, TimeSpan.FromMilliseconds(-1));
    }

    public void Test_Sleep()
    {
        for (int i = 0; i < 10; i++)
        {
            var now = DateTime.UtcNow;
            var nextDT = RoundUpFuzzy(now, TimeSpan.FromMinutes(1));
            var waitTS = nextDT.Subtract(now);
            Console.WriteLine("Now: " + now.ToString("HH:mm:ss.fff") + " nextDT: " + nextDT.ToString("HH:mm:ss.fff") + " waitMS: " + waitTS.TotalMilliseconds);
            System.Threading.Thread.Sleep(waitTS);
        }
    }

    DateTime RoundUpFuzzy(DateTime dt, TimeSpan d)
    {
        int n = 1;
        if (dt.Millisecond > 900)
            n = 2;
        return new DateTime(((dt.Ticks + (d.Ticks * n) - 1) / d.Ticks) * d.Ticks);
    }
}

Answer 1

为了避免这些问题，我建议使用Quartz.Net（https://www.quartz-scheduler.net/）。它易于使用

Answer 2

线程和计时器有一个resolution of around 15 ms，所以你不能指望比这更好......

对于精确时间测量，您必须使用StopWatch class from the .Net，因为这是基于高分辨率频率。

为什么我的计时器会提早开始？

2 个答案: