Question

我正在编写一个应用程序，它使用计时器在某些事件发生时在屏幕上显示倒计时。我想重用计时器，因为它对应用程序中的一些东西很方便，所以我指定了我想要围绕计时器的单词。例如，以下函数调用：

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

会显示：

You have 1 minute 30 seconds until the computer reboots

然后倒计时。

我使用以下代码：

    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)

目前它立即调用重启。

任何指针都是最受欢迎的！

谢谢，

本

Answer 1

就个人而言，我建议在CountdownTimer结束时进行回调 - 也许以Action作为参数，这样当它完成时就会被调用。

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();
        }
    }

然后你可以将你的用法改为：

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

Answer 2

您可以使用AutoResetEvent：

System.Threading.AutoResetEvent _countdownFinishedEvent
    = new AutoResetEvent(false);

在CountdownTimer：

的末尾添加此内容

_countdownFinishedEvent.WaitOne();

然后在Countdown_Tick之后的Countdown.Stop()中添加此内容：

_countdownFinishedEvent.Set();

你如何在C＃中运行同步计时器？

2 个答案: