单击按钮停止 DispatcherTimer

Question

当我点击我的停止按钮时，我的计时器仍在倒计时，即使我告诉它停止。

我当前的相关代码：

我在这里命名计时器，因为我也需要访问它们以使用 stop/start 全部按钮。

namespace Row_Interface
{
    public partial class MainWindow : Window
    {
        //Declare the timers here, so the stop all button can access them as well
        DispatcherTimer motorTimer_1 = new DispatcherTimer();
        TimeSpan motorCycleTime_1 = TimeSpan.FromSeconds(0);

当我点击打开按钮时，IndividualTestStart 方法被调用并传递相关参数：

public void motorOnBtn_1_Click(object sender, RoutedEventArgs e)
        {
            IndividualTestStart(motorOnBtn_1, motorOffBtn_1, motorTimer_1, motorCycleTime_1, timeUntilmotorCycle_1, motorTestCycles_1);
        }

当我点击关闭按钮时，我想停止那个计时器，这样循环就永远不会结束：

        private void motorOffBtn_1_Click(object sender, RoutedEventArgs e)
        {
            motorTimer_1.Stop();
            motorOnBtn_1.IsEnabled = true; //Enables the start test button
            motorOffBtn_1.IsEnabled = false; //Disables the stop test button

        }

点击开始时调用。我最终会为停止按钮提供类似的东西，但我会一步一个脚印：

private void IndividualTestStart(Button startButton, Button stopButton, DispatcherTimer dispatcherTimer, TimeSpan timeSpan, TextBox timeRemaining, TextBox cycleCount)
        {
            stopButton.IsEnabled = true; //Enables the stop button

            //Set the time to run. This will be set from the database eventually.
            timeSpan = TimeSpan.FromSeconds(10);

            //Set up the new timer. Updated every second.
            dispatcherTimer = new DispatcherTimer(new TimeSpan(0, 0, 1), DispatcherPriority.Normal, delegate
            {
                timeRemaining.Text = timeSpan.ToString("c"); //Sets the text in the textbox to the time remaining in the timer
                startButton.IsEnabled = false; //Disables the start test button once the test is started
                if (timeSpan == TimeSpan.Zero) //Checks to seee if the time has run out
                {
                    dispatcherTimer.Stop(); //Stops the timer once the time has run out
                    startButton.IsEnabled = true; //Enables the start test button
                    int initialCycleCount = 0;
                    initialCycleCount++;
                    cycleCount.Text = initialCycleCount.ToString();
                    stopButton.IsEnabled = false;//Disables the stop button

                }
                timeSpan = timeSpan.Add(TimeSpan.FromSeconds(-1)); //Subtracts one second each time the timer "ticks"
            }, Application.Current.Dispatcher);  //runs within the UI thread

            dispatcherTimer.Start(); //Starts the timer 
        }
}

当我单击停止按钮时，我希望文本框中的计时器停止倒计时。但是，它一直在滴答作响。当我点击停止时，开始按钮被重新启用，所以我知道它触发了事件处理程序中的代码。但它并没有停止计时器。

现在不开始新的计时器。新代码：

        public void motorOnBtn_1_Click(object sender, RoutedEventArgs e)
        {
            IndividualTestStart(motorOnBtn_1, motorOffBtn_1, motorTimer_1, motorCycleTime_1, timeUntilmotorCycle_1, motorTestCycles_1);
        }

        private void IndividualTestStart(Button startButton, Button stopButton, DispatcherTimer dispatcherTimer, TimeSpan timeSpan, TextBox timeRemaining, TextBox cycleCount)
        {
            stopButton.IsEnabled = true; //Enables the stop button

            //Set the time to run. This will be set from the database eventually.
            timeSpan = TimeSpan.FromSeconds(10);

            {
                timeRemaining.Text = timeSpan.ToString("c"); //Sets the text in the textbox to the time remaining in the timer
                startButton.IsEnabled = false; //Disables the start test button once the test is started
                if (timeSpan == TimeSpan.Zero) //Checks to seee if the time has run out
                {
                    dispatcherTimer.Stop(); //Stops the timer once the time has run out
                    startButton.IsEnabled = true; //Enables the start test button
                    int initialCycleCount = 0;
                    initialCycleCount++;
                    cycleCount.Text = initialCycleCount.ToString();
                    stopButton.IsEnabled = false;//Disables the stop button

                }
                timeSpan = timeSpan.Add(TimeSpan.FromSeconds(-1)); //Subtracts one second each time the timer "ticks"
            };  //runs within the UI thread

            dispatcherTimer.Start(); //Starts the timer 
        }

Answer 1

您的代码中的问题是，您使用不执行任何操作的 DispatcherTimer 初始化 motorTimer_1，然后将 motorTimer_1 作为 dispatcherTimer 参数传递，然后用新创建的不同 DispatcherTimer 替换参数的值。

新计时器工作正常，但是当您在 motorTimer_1 上调用停止时，没有任何反应，因为那不是运行ning 的计时器。您可以简单地将新的 DispatcherTimer 直接分配给 IndividualTestStart() 中的 motorTimer_1，但是您在参数化 IndividualTestStart() 中的所有内容时遇到了很大的麻烦，因此它可以与不同的 DispatcherTimer 一起工作。

相反，我们将执行以下操作：没有理由 传递 DispatcherTimer。 IndividualTestStart() 必须创建 DispatcherTimer 才能对其进行初始化。好的，让我们运行开始吧。它将创建一个新的 return 它。

private DispatcherTimer IndividualTestStart(Button startButton, Button stopButton, 
    TimeSpan timeSpan, TextBox timeRemaining, TextBox cycleCount)
{
    stopButton.IsEnabled = true; //Enables the stop button

    //Set the time to run. This will be set from the database eventually.
    timeSpan = TimeSpan.FromSeconds(10);

    //  Set up the new timer. Updated every second.
    var dispatcherTimer = new DispatcherTimer(new TimeSpan(0, 0, 1), DispatcherPriority.Normal, delegate
    {
        timeRemaining.Text = timeSpan.ToString("c"); //Sets the text in the textbox to the time remaining in the timer
        startButton.IsEnabled = false; //Disables the start test button once the test is started
        if (timeSpan == TimeSpan.Zero) //Checks to seee if the time has run out
        {
            dispatcherTimer.Stop(); //Stops the timer once the time has run out
            startButton.IsEnabled = true; //Enables the start test button
            int initialCycleCount = 0;
            initialCycleCount++;
            cycleCount.Text = initialCycleCount.ToString();
            stopButton.IsEnabled = false;//Disables the stop button

        }
        timeSpan = timeSpan.Add(TimeSpan.FromSeconds(-1)); //Subtracts one second each time the timer "ticks"
    }, Application.Current.Dispatcher);  //runs within the UI thread

    dispatcherTimer.Start(); //Starts the timer 

    return dispatcherTimer;
}

public void motorOnBtn_1_Click(object sender, RoutedEventArgs e)
{
    if (motorTimer_1 == null)
    {
        //  Create/initialize a new timer and assign it to motorTimer_1
        motorTimer_1 = IndividualTestStart(motorOnBtn_1, motorOffBtn_1, 
            motorCycleTime_1, timeUntilmotorCycle_1, motorTestCycles_1);
    }
    else
    {
        //  It's already there, just start it. 
        motorTimer_1.Start();
    }
}

由于这是 WPF，您需要编写一个拥有 DispatcherTimer 的视图模型 class TimerThing（想一个更好的名字），两个用于启动和停止它的命令，以及一个 public bool 属性表示它是否是运行ning。 IndividualTestStart() 应该是 class 的一个方法。父视图模型将有一个包含任意数量的 TimerThing 的 ObservableCollection<TimerThing>，这将显示在 ItemsControl 中，该 ItemTemplate 创建绑定到 Start 和 Stop 命令的按钮。上面的代码看起来会很不一样，因为 C# 代码的 none 知道有关按钮的任何信息：相反，项目模板 XAML 中的按钮将通过绑定 enabled/disabled。

单击按钮停止 DispatcherTimer

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