如何使用 .NET Timer 类在特定时间触发事件? [英] How to use the .NET Timer class to trigger an event at a specific time?

问题描述

我希望在我的应用程序中触发一个事件，该事件在白天的某个时间连续运行，例如下午 4:00.我想过每秒运行一次计时器，当时间等于下午 4:00 时运行事件.这样可行.但我想知道是否有一种方法可以在下午 4:00 获得一次回调而不必继续检查.

I would like to have an event triggered in my app which runs continuously during the day at a certain time, say at 4:00pm. I thought about running the timer every second and when the time is equal to 4:00pm run the event. That works. But I'm wondering if there's a way to just get the callback once at 4:00pm and not having to keep checking.

推荐答案

使用 System.Threading.Timer 类?

var t = new Timer(TimerCallback);

// Figure how much time until 4:00
DateTime now = DateTime.Now;
DateTime fourOClock = DateTime.Today.AddHours(16.0);

// If it's already past 4:00, wait until 4:00 tomorrow    
if (now > fourOClock)
{
    fourOClock = fourOClock.AddDays(1.0);
}

int msUntilFour = (int)((fourOClock - now).TotalMilliseconds);

// Set the timer to elapse only once, at 4:00.
t.Change(msUntilFour, Timeout.Infinite);

请注意，如果您使用 System.Threading.Timer，TimerCallback 指定的回调将在线程池(非 UI)线程上执行——因此如果您计划在 4:00 对您的 UI 执行某些操作，您必须适当地编组代码(例如，在 Windows 窗体应用程序中使用 Control.Invoke 或 Dispatcher.在 WPF 应用程序中调用).

Note that if you use a System.Threading.Timer, the callback specified by TimerCallback will be executed on a thread pool (non-UI) thread—so if you're planning on doing something with your UI at 4:00, you'll have to marshal the code appropriately (e.g., using Control.Invoke in a Windows Forms app, or Dispatcher.Invoke in a WPF app).

这篇关于如何使用 .NET Timer 类在特定时间触发事件?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！