Question

我制作了一个Canvas（playArea），我在其上添加了1个Bee（使用playArea.children.Add(bee)）。我还会在box的随机点上每X秒添加一个新的playArea。我可以使用bee和Storyboard将DoubleAnimation从当前点移动到我点击的位置。

我想要做的是删除box bee正在传递的playAre.Children.Remove(box)（就像它应该bee一样。我只是无法弄明白如何检查。

这是一个例子。如果我点击A，我的EventHandler会转到那个点并删除它上面的3个方框。我在想我应该使用自己的//moving the bee to the position which I got from Point p = Mouse.GetPosition(playArea); public static void MoveBee(UIElement element, double toX, double toY) { double fromX = Canvas.GetLeft(element); double fromY = Canvas.GetTop(element); Storyboard storyboard = new Storyboard(); DoubleAnimation animationX = CreateDoubleAnimation(element, fromX, toX, new PropertyPath(Canvas.LeftProperty)); DoubleAnimation animationY = CreateDoubleAnimation(element, fromY, toY, new PropertyPath(Canvas.TopProperty)); storyboard.Children.Add(animationX); storyboard.Children.Add(animationY); storyboard.Begin(); } public static DoubleAnimation CreateDoubleAnimation(UIElement element, double from, double to, PropertyPath propertyToAnimate) { DoubleAnimation animation = new DoubleAnimation(); Storyboard.SetTarget(animation, element); Storyboard.SetTargetProperty(animation, propertyToAnimate); animation.From = from; animation.To = to; animation.Duration = TimeSpan.FromSeconds(3); return animation; } public void DrawBox() { BoxControl newBox = new BoxControl(); playArea.Children.Add(newBox); Canvas.SetTop(newBox, random.Next(0, 419)); Canvas.SetLeft(newBox, random.Next(0, 792)); }（我不知道如何制作自己的，但这是另一个问题）。所以，我应该做什么，或者我应该做什么条件？

编辑：以下是我使用的方法的样子。我在开始时做了什么，我只画一只蜜蜂并将它添加到我的画布上，每隔X秒我就在随机位置添加一个新盒子

curl https://somedomain.com/somepath.json

Answer 1

您可以在动画上使用CurrentTimeInvalidated事件处理程序。有关详细信息，请参阅下面的代码。

Valid XHTML

public partial class MainWindow : Window
{
    public Random Rng { get; set; }

    public MainWindow()
    {
        InitializeComponent();
        Rng = new Random(0);

        do
        {
            AddBoxToRandomPointInPlayArea();
        } while (PlayArea.Children.Count < 10);

    }

    private void AddBoxToRandomPointInPlayArea()
    {
        var x = Rng.Next(0, Convert.ToInt32(PlayArea.Width));
        var y = Rng.Next(0, Convert.ToInt32(PlayArea.Height));

        var box = new Rectangle
        {
            Height = 10,
            Width = 30,
            Fill = Brushes.Brown
        };

        PlayArea.Children.Add(box);

        Canvas.SetLeft(box, x);
        Canvas.SetTop(box, y);
    }

    private void PlayArea_MouseDown(object sender, MouseButtonEventArgs e)
    {
        var x = Canvas.GetLeft(Bee);
        var y = Canvas.GetTop(Bee);

        var storyboard = new Storyboard();

        var xTranslation = new DoubleAnimation(x, e.GetPosition(PlayArea).X, new Duration(new TimeSpan(0, 0, 5)));
        Storyboard.SetTargetProperty(xTranslation, new PropertyPath(Canvas.LeftProperty));
        xTranslation.CurrentTimeInvalidated += CheckForCollidingBoxesAndRemoveIfNeeded;

        storyboard.Children.Add(xTranslation);

        var yTranslation = new DoubleAnimation(y, e.GetPosition(PlayArea).Y, new Duration(new TimeSpan(0, 0, 5)));
        Storyboard.SetTargetProperty(yTranslation, new PropertyPath(Canvas.TopProperty));
        yTranslation.CurrentTimeInvalidated += CheckForCollidingBoxesAndRemoveIfNeeded; 

        storyboard.Children.Add(yTranslation);

        Bee.BeginStoryboard(storyboard);
    }


    private void CheckForCollidingBoxesAndRemoveIfNeeded(object sender, EventArgs eventArgs)
    {
        var idxToRemoveAt = GetIndexOfBoxCollidingWithBee;
        if ( idxToRemoveAt != -1 )
        {
            PlayArea.Children.RemoveAt(idxToRemoveAt);
        }
    }

    /// <summary>
    /// returns 0 if no boxes collide, otherwise the number is the index of the box in the 
    /// </summary>
    public int GetIndexOfBoxCollidingWithBee
    {
        get
        {
            var beeTopLeft = PointToScreen(new Point(Canvas.GetLeft(Bee), Canvas.GetTop(Bee))); // local to world coordinates
            var beeCentroid = new Point((beeTopLeft.X + Bee.ActualWidth) * 0.5, (beeTopLeft.Y + Bee.ActualHeight) * 0.5); // center point of bee

            for (var idx = 0; idx < PlayArea.Children.Count; idx++)
            {
                var child = PlayArea.Children[idx];
                var currentBoxInSearch = child as Rectangle;
                if (currentBoxInSearch != null)
                {
                    var boxTopLeft = PointToScreen(new Point(Canvas.GetLeft(currentBoxInSearch), Canvas.GetTop(currentBoxInSearch))); // local to world coordinates
                    var boxCentroid = new Point((boxTopLeft.X + currentBoxInSearch.ActualWidth) * 0.5, (boxTopLeft.Y + currentBoxInSearch.ActualHeight) * 0.5); // center point of bee

                    var xCollided = false;
                    var yCollided = false;

                    if (Math.Abs(beeCentroid.X - boxCentroid.X) < Bee.ActualWidth*0.5)
                        xCollided = true;

                    if (Math.Abs(beeCentroid.Y - boxCentroid.Y) < Bee.ActualHeight*0.5)
                        yCollided = true;

                    if (xCollided && yCollided)
                        return idx;
                }
            }

            return -1;
        }
    }
}

C＃当另一个UIElement通过他时删除UIElement

1 个答案: