Question

对于我的学校项目，我正在尝试一个弹丸模拟，但决定使用故事板（不确定这是否是正确的想法），所以到目前为止我的代码。从标题中可以看出，我在尝试执行时遇到了错误 ellipseStoryboard.Begin（本）; 但我不知道我做错了什么。谢谢你的帮助！

我的代码：

void onTimedEvent(Object sender, ElapsedEventArgs t, particle newProjectile, double TimeInterval, int i, Path myPath, Canvas AnimationCanvas)
{
    this.Dispatcher.Invoke((Action)(() =>
    {
        AnimationCanvas.Children.Clear();
    }));

    PointAnimation myPointAnimation = new PointAnimation();
    myPointAnimation.Duration = TimeSpan.FromSeconds(TimeInterval);
    myPointAnimation.RepeatBehavior = new RepeatBehavior(1);
    myPointAnimation.From = new System.Windows.Point(newProjectile.HDisplacement[i], newProjectile.VDisplacement[i]);
    myPointAnimation.To = new System.Windows.Point(newProjectile.HDisplacement[i + 1], newProjectile.VDisplacement[i + 1]);
    Storyboard.SetTargetName(myPointAnimation, "MyAnimatedEllipseGeometry");
    Storyboard.SetTargetProperty(myPointAnimation, new PropertyPath(EllipseGeometry.CenterProperty));
    Storyboard ellipseStoryboard = new Storyboard();
    ellipseStoryboard.Children.Add(myPointAnimation);
    this.Dispatcher.Invoke((Action)(() =>
    {
        myPath.Loaded += delegate(object sender1, RoutedEventArgs e)
        {
            ellipseStoryboard.Begin(this);
        };
    }));
    this.Dispatcher.Invoke((Action)(() =>
    {
        AnimationCanvas.Children.Add(myPath);
    }));

}

编辑：我已经计算了实际的位移点并将它们放在一个数组中

Answer 1

您可能不需要更多：

myPath.Loaded +=
    (o, e) =>
    {
        var myPointAnimation = new PointAnimation
        {
            Duration = TimeSpan.FromSeconds(TimeInterval),
            From = new Point(...),
            To = new Point(...)
        };
        MyAnimatedEllipseGeometry.BeginAnimation(
            EllipseGeometry.CenterProperty, myPointAnimation);
    };

虽然弹丸的x和y坐标的独立动画（例如，通过故事板中的两个动画）和y坐标的二次缓动函数可以模拟重力，但你最好使用frame-based animation具有时间依赖性运动学的真实物理模拟。

上述简单版本可能如下所示：

<Path Fill="Black">
    <Path.Data>
        <EllipseGeometry x:Name="projectileGeometry" RadiusX="5" RadiusY="5"/>
    </Path.Data>
</Path>

使用以下代码隐藏，其中您有射弹的位置，速度和加速度，以及计算运动学的Rendering事件处理程序。

private Point position; // in pixels
private Vector velocity; // in pixels per second
private Vector acceleration; // in pixels per square second
private DateTime time;

public MainWindow()
{
    InitializeComponent();
    Loaded += OnLoaded;
}

private void OnLoaded(object sender, RoutedEventArgs e)
{
    position = new Point(100, 100);
    velocity = new Vector(50, -50); // y direction is downwards
    acceleration = new Vector(0, 20); // y direction is downwards
    time = DateTime.Now;
    CompositionTarget.Rendering += OnRendering;
}

private void OnRendering(object sender, EventArgs e)
{
    var t = DateTime.Now;
    var dt = (t - time).TotalSeconds;
    time = t;

    position += velocity * dt;
    velocity += acceleration * dt;

    projectileGeometry.Center = position;

    if (position.Y > ActualHeight)
    {
        CompositionTarget.Rendering -= OnRendering;
    }
}

Answer 2

看起来你正试图从计时器开始动画。如果您收到线程错误，则可能是错误的线程。而不是使用Dispatcher.Invoke编组，只需使用DispatcherTimer，这将确保您的回调在UI线程上。

而不是：

var timer = new System.Timers.Timer(1000);
timer.Elapsed += tmrHandler;
timer.Enabled = true;

使用

var timer = new DispatcherTimer(DispatcherPriority.Normal);
timer.Interval = TimeSpan.FromSeconds(1);
timer.Tick += tmrHandler;
timer.IsEnabled = true;

错误：调用线程无法访问此对象，因为另一个线程拥有它。故事板模拟

2 个答案: