windows-phone-7 - 如何暂停 DispatchTimer？

Question

如何在 WP7 中暂停计时器？在我的应用程序中，我想暂停和恢复计时器。但是 DispatcherTimer 只有启动和停止。如何暂停计时器？

Answer 1

试试这个：定义一个全局变量：

private static DateTime EndTime { get; set; }

然后，当按下 Start 按钮时，您进行以下检查以确定计时器是否已停止或暂停：

private void btnStartClick(object sender, RoutedEventArgs e)
{
    if (this.dispatcherTimer == null)
    {
        this.dispatcherTimer = new DispatcherTimer();
        this.dispatcherTimer.Interval = TimeSpan.FromMilliseconds(100);
        this.dispatcherTimer.Tick += new EventHandler(dispatcherTimer_Tick);
    }

    if (this.EndTime == DateTime.MinValue)
    {
        this.EndTime = DateTime.Now + (TimeSpan)this.timeSpan.Value;
    }

    this.dispatcherTimer.Start();
}

接下来，当按下暂停按钮时，您可以停止计时器，因为下次按下开始按钮时，您将通过上述检查：

private void btnPauseClick(object sender, RoutedEventArgs e)
{
    this.dispatcherTimer.Stop();
}

Answer 2

对于暂停/恢复功能，您必须将其构建到您的 Tick 处理程序中，启动和停止计时器。

如果您的计时器间隔约为 60 秒，请尝试以下操作：

dispatcher_Timer.Interval = TimeSpan.Fromseconds(30);

dispatcher_Timer.Tick += new EventHandler(dispatcherTimer_Tickon);

dispatcher_Timer.Start();

private void dispatcherTimer_Tickon(object sender, EventArgs e)
{
    dispatcher_Timer.Tick -= new EventHandler(dispatcherTimer_Tickon);
    // Do the work for 30 seconds and pause it using stop             
    dispatcher_Timer.Stop();

    dispatcher_Timer.Tick += new EventHandler(dispatcherTimer2_Tickon);
    dispatcher_Timer.Start();
}

private void dispatcherTimer2_Tickon(object sender, EventArgs e)
{
    dispatcher_Timer.Tick -= new EventHandler(dispatcherTimer2_Tickon);
    // Do the remaining work for 30 seconds and pause it using stop             
    dispatcher_Timer.Stop();
}

Answer 3

尝试将 IsEnabled 属性设置为 false 以停止它，然后在您希望它继续时返回 true。

Answer 4

没有办法暂停计时器，然后让它从中断的地方继续。IsEnabled 只调用 Start 和 Stop。

您需要创建自己的计时器才能拥有此功能。

Answer 5

试试这个代码：

public class DispatcherTimerEx : DispatcherTimer
{
    public new TimeSpan Interval
    {
        get => maxInterval;
        set => base.Interval = maxInterval = value;
    }

    public new bool IsEnabled
    {
        get => base.IsEnabled;
        set
        {
            if (value == base.IsEnabled)
                return;
            if (value)
                this.Start();
            else
                this.Stop();
        }
    }

    TimeSpan maxInterval;
    DateTime startTime = DateTime.MinValue;
    DateTime stopTime = DateTime.MinValue;

    public DispatcherTimerEx()
    {
        base.Tick += OnTick;
    }

    public DispatcherTimerEx(DispatcherPriority priority) : base(priority)
    {
        base.Tick += OnTick;
    }

    public DispatcherTimerEx(DispatcherPriority priority, Dispatcher dispatcher) : base(priority, dispatcher)
    {
        base.Tick += OnTick;
    }

    public DispatcherTimerEx(TimeSpan interval, DispatcherPriority priority, EventHandler callback,
        Dispatcher dispatcher) : base(interval, priority, callback, dispatcher)
    {
        base.Tick += OnTick;
    }

    public new void Start()
    {
        base.Start();
        startTime = DateTime.Now;
        stopTime = DateTime.MinValue;
    }

    void OnTick(object sender, EventArgs e)
    {
        startTime = DateTime.Now;
        if (base.Interval == maxInterval) return;

        base.Stop();
        base.Interval = maxInterval;
        base.Start();
    }


    public void Pause()
    {
        base.Stop();
        stopTime = DateTime.Now;
    }

    public void Resume()
    {
        if (startTime == DateTime.MinValue)
            startTime = DateTime.Now;

        if (stopTime == DateTime.MinValue)
        {
            base.Interval = maxInterval;
        }
        else
        {
            base.Interval = maxInterval - (stopTime - startTime);
            stopTime = DateTime.MinValue;
        }

        base.Start();
    }
}

我在这里添加了Puase()方法Resume()。

Answer 6

你可以通过这个简单的技巧轻松地暂停 Dispatcher，如果你将时间间隔设置为零呢？

这将暂停调度程序

 dispatcherTimer.Interval.Subtract(dispatcherTimer.Interval); 

再次恢复 dispatchTimer 只需将时间跨度添加到 Interval。

dispatcherTimer.Interval = new TimeSpan(0, 0, 0, 5); // this will

或者

dispatcherTimer.Interval = TimeSpan.FromMilliseconds(100);