DateChange的活动在午夜 [英] Event for DateChange at midnight

问题描述

可能重复：

后台工作者是否在午夜检查？

是否有一个我可以注册的SystemEvent并在日期更改后的午夜发布？

Is there a SystemEvent which I can register to and which will be published at midnight, when the Date has changed?

推荐答案

这是我用来处理此问题的课程。类似于@sll的答案，但是考虑到系统时间的变化，并且还会触发每个午夜，而不是仅触发一次。

Here's a class I use to handle this. It's similar to @sll's answer, however takes into account the system time changing and also will trigger each midnight instead of only once.

static class MidnightNotifier
{
    private static readonly Timer timer;

    static MidnightNotifier()
    {
        timer = new Timer(GetSleepTime());
        timer.Elapsed += (s, e) =>
        {
            OnDayChanged();
            timer.Interval = GetSleepTime();
        };
        timer.Start();

        SystemEvents.TimeChanged += OnSystemTimeChanged;
    }

    private static double GetSleepTime()
    {
        var midnightTonight = DateTime.Today.AddDays(1);
        var differenceInMilliseconds = (midnightTonight - DateTime.Now).TotalMilliseconds;
        return differenceInMilliseconds;
    }

    private static void OnDayChanged()
    {
        var handler = DayChanged;
        if (handler != null)
            handler(null, null);
    }

    private static void OnSystemTimeChanged(object sender, EventArgs e)
    {
        timer.Interval = GetSleepTime();
    }

    public static event EventHandler<EventArgs> DayChanged;
}

由于它是静态类，因此您可以使用以下代码来订阅事件：

Since it's a static class, you can subscribe to the event using code like:

MidnightNotifier.DayChanged += (s, e) => { Console.WriteLine("It's midnight!"); };

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