我真的不写一个闹钟应用程序，但它有助于说明我的问题。

I'm not really writing an alarm clock application, but it will help to illustrate my question.

让我们说，我在我的应用程序有一个方法，我想这个方法被称为在小时每隔一小时（如下午7:00，下午8点00分，下午九时00分等等）。我的可以的创建一个定时器并设置其间隔为3600000，但最终这将同步漂移与系统时钟。或者我的可以的使用，而（）循环与 Thread.sleep代码（N）来定期检查系统时间，并调用方法时达到所需的时间，但我不喜欢这样或者（ Thread.sleep代码（N）是一个大$ C $ Ç气味对我来说）。

Let's say that I have a method in my application, and I want this method to be called every hour on the hour (e.g. at 7:00 PM, 8:00 PM, 9:00 PM etc.). I could create a Timer and set its Interval to 3600000, but eventually this would drift out of sync with the system clock. Or I could use a while() loop with Thread.Sleep(n) to periodically check the system time and call the method when the desired time is reached, but I don't like this either (Thread.Sleep(n) is a big code smell for me).

我正在寻找的是.NET中的一些方法，让我传递了一个未来的DateTime对象和方法，委托或事件处理程序，但我一直没能找到任何这样的事情。我怀疑有Win32 API的，这是否在一个方法，但我一直没能找到，无论是。

What I'm looking for is some method in .Net that lets me pass in a future DateTime object and a method delegate or event handler, but I haven't been able to find any such thing. I suspect there's a method in the Win32 API that does this, but I haven't been able to find that, either.

推荐答案

或者，你可以用1秒的间隔创建一个计时器，并查看当前的时间每一秒，直到事件时间到达，如果是这样，你提高你的事件。

Or, you could create a timer with an interval of 1 second and check the current time every second until the event time is reached, if so, you raise your event.

您可以做一个简单的包装为：

You can make a simple wrapper for that :

public class AlarmClock
{
    public AlarmClock(DateTime alarmTime)
    {
        this.alarmTime = alarmTime;

        timer = new Timer();
        timer.Elapsed += timer_Elapsed;
        timer.Interval = 1000;
        timer.Start();

        enabled = true;
    }

    void  timer_Elapsed(object sender, ElapsedEventArgs e)
    {
        if(enabled && DateTime.Now > alarmTime)
        {
            enabled = false;
            OnAlarm();
            timer.Stop();
        }
    }

    protected virtual void OnAlarm()
    {
        if(alarmEvent != null)
            alarmEvent(this, EventArgs.Empty);
    }


    public event EventHandler Alarm
    {
        add { alarmEvent += value; }
        remove { alarmEvent -= value; }
    }

    private EventHandler alarmEvent;
    private Timer timer;
    private DateTime alarmTime;
    private bool enabled;
}

用法：

AlarmClock clock = new AlarmClock(someFutureTime);
clock.Alarm += (sender, e) => MessageBox.Show("Wake up!");

请注意code以上是非常粗略的，而不是线程安全的。

Please note the code above is very sketchy and not thread safe.