Question

我正在尝试获取动画开始和停止的确切时间。使用AnimationClock开始动画。我尝试听过AnimationClock的CurrentStateInvalidated事件，但是当我检查自调用AnimationClock.Controller.Begin（）以来经过的时间时，该时间总是少于动画的持续时间（30-50 ms）。动画似乎立即开始。以下代码示例应对此进行演示。

public partial class AnimationTest : Window {
    private Stopwatch _stopwatch;
    private AnimationClock _clock;
    public ICommand StartCommand => new RelayCommand(Start);

    public AnimationTest() {
        InitializeComponent();
        _stopwatch = new Stopwatch();
        var a = CreateAnimation();
        _clock = a.CreateClock();
        MyRectangle.ApplyAnimationClock(MarginProperty, _clock);
        _clock.Controller.Stop();
        _clock.CurrentStateInvalidated += AnimationClock_CurrentStateInvalidated;
        DataContext = this;
    }

    private ThicknessAnimationUsingKeyFrames CreateAnimation() {
        ThicknessAnimationUsingKeyFrames a = new ThicknessAnimationUsingKeyFrames();
        var duration = 0;
        var durationPerKeyFrame = 400;
        a.KeyFrames.Add(new LinearThicknessKeyFrame(new Thickness(400, 300, 0, 0), TimeSpan.FromMilliseconds(duration += durationPerKeyFrame)));
        a.KeyFrames.Add(new LinearThicknessKeyFrame(new Thickness(0, 0, 0, 0), TimeSpan.FromMilliseconds(duration += durationPerKeyFrame)));
        a.Duration = TimeSpan.FromMilliseconds(duration);
        a.FillBehavior = FillBehavior.Stop;
        return a;
    }

    private void WindowLoaded(object sender, RoutedEventArgs e) {

    }
    private void Start() {
        _clock.Controller.Begin();
        _stopwatch.Start();
    }

    private void AnimationClock_CurrentStateInvalidated(object sender, EventArgs e) {
        Clock clock = (Clock) sender;
        if (clock.CurrentState == ClockState.Active) {
            Console.WriteLine("time since start was called " + _stopwatch.ElapsedMilliseconds + " ms");
            _stopwatch.Restart();
        }
        if (clock.CurrentState == ClockState.Stopped) {
            Console.WriteLine("time since animation started " + _stopwatch.ElapsedMilliseconds + " ms");
            _stopwatch.Reset();
        }          
    }
}

我认为动画实际上比我指定的持续时间短，动画停止之前会触发CurrentStateInvalidated事件，或者动画开始时存在延迟，这会导致StopWatch.Restart（）延迟。我怎么知道呢？

在记录眼动数据和音频时，该动画用作刺激，因此我需要确保在动画开始时就开始眼动仪和音频记录，或者至少知道应该如何调整时间因此可以同步播放。我需要寻找WPF以外的其他动画框架吗？

在WPF中使用AnimationClock定时动画

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