c# - 如何在 C# 中运行同步计时器？

Question

我正在编写一个应用程序，它使用计时器在屏幕上显示某个事件发生时的倒计时。我想重复使用计时器，因为它对应用程序中的一些事情很方便，所以我指定了我想要环绕计时器的词。例如，下面的函数调用:

CountdownTimer(90, "You have ", " until the computer reboots");

会显示:

You have 1 minute 30 seconds until the computer reboots

然后倒数。

我正在使用以下代码:

    private void CountdownTimer(int Duration, string Prefix, string Suffix)
    {
        Countdown = new DispatcherTimer();
        Countdown.Tick += new EventHandler(Countdown_Tick);
        Countdown.Interval = new TimeSpan(0, 0, 1);

        CountdownTime = Duration;
        CountdownPrefix = Prefix;
        CountdownSuffix = Suffix;
        Countdown.Start();
    }

    private void Countdown_Tick(object sender, EventArgs e)
    {
        CountdownTime--;
        if (CountdownTime > 0)
        {
            int seconds = CountdownTime % 60;
            int minutes = CountdownTime / 60;

            Timer.Content = CountdownPrefix;

            if (minutes != 0)
            {
                Timer.Content = Timer.Content + minutes.ToString() + @" minute";
                if (minutes != 1) { Timer.Content = Timer.Content + @"s"; }
                Timer.Content = Timer.Content + " ";
            }

            if (seconds != 0)
            {
                Timer.Content = Timer.Content + seconds.ToString() + @" second";
                if (seconds != 1) { Timer.Content = Timer.Content + @"s"; }
            }

            Timer.Content = Timer.Content + CountdownSuffix;

        }
        else
        {
            Countdown.Stop();
        }

    }

如何使它同步运行？例如，我希望以下内容等待 90 秒然后重新启动:

CountdownTimer(90, "You have ", " until the computer reboots");
ExitWindowsEx(2,0)

而目前它会立即调用重启。

欢迎任何指点!

谢谢，

本

Answer 1

就我个人而言，我建议在您的 CountdownTimer 结束时进行回调 - 也许将 Action 作为参数，以便在它完成时调用它。

private Action onCompleted;
private void CountdownTimer(int Duration, string Prefix, string Suffix, Action callback)
{
    Countdown = new DispatcherTimer();
    Countdown.Tick += new EventHandler(Countdown_Tick);
    Countdown.Interval = new TimeSpan(0, 0, 1);

    CountdownTime = Duration;
    CountdownPrefix = Prefix;
    CountdownSuffix = Suffix;
    Countdown.Start();

    this.onCompleted = callback;
}
...
    else
    {
        Countdown.Stop();
        Action temp = this.onCompleted; // thread-safe test for null delegates
        if (temp != null)
        {
            temp();
        }
    }

然后您可以将您的用法更改为:

CountdownTimer(90, "You have ", " until the computer reboots", 
    () => ExitWindowsEx(2,0));