带有ListBox的FluidMoveBehavior

Question

我正在努力让FluidMoveBehavior工作，但无论我尝试什么都没有动画。它只是正常添加/删除项目而没有任何褪色/滑入/滑出。我从网上下载的其他例子工作得很好，连接似乎很简单。我在下面的代码中做错了什么？

<Window
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:SampleData="clr-namespace:Expression.Blend.SampleData.SampleDataSource"           
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
    xmlns:ei="http://schemas.microsoft.com/expression/2010/interactions"
    mc:Ignorable="d"
    x:Class="WpfApplication1.MainWindow"
    x:Name="Window"
    Title="MainWindow"
    Width="640" Height="480">

    <Window.Resources>      
        <DataTemplate x:Key="ItemTemplate">
            <StackPanel Background="{Binding MyColor}">
                <TextBlock Text="{Binding Name}"/>              
            </StackPanel>
        </DataTemplate>
        <ItemsPanelTemplate x:Key="ItemsPanelTemplate1">
            <StackPanel>
                <i:Interaction.Behaviors>
                    <ei:FluidMoveBehavior Duration="0:0:5" AppliesTo="Children">
                        <ei:FluidMoveBehavior.EaseY>
                            <CubicEase EasingMode="EaseInOut"/>
                        </ei:FluidMoveBehavior.EaseY>
                        <ei:FluidMoveBehavior.EaseX>
                            <CubicEase EasingMode="EaseInOut"/>
                        </ei:FluidMoveBehavior.EaseX>
                    </ei:FluidMoveBehavior>
                </i:Interaction.Behaviors>  
            </StackPanel>
        </ItemsPanelTemplate>
    </Window.Resources>

    <Grid x:Name="LayoutRoot">
        <ListBox x:Name="lbTest" Margin="8,47,8,8" ItemTemplate="{DynamicResource ItemTemplate}" ItemsPanel="{DynamicResource ItemsPanelTemplate1}" />
        <Button Content="Add" HorizontalAlignment="Left" Height="34" Margin="8,9,0,0" VerticalAlignment="Top" Width="100" Click="OnAdd"/>
        <Button Content="Remove" HorizontalAlignment="Left" Height="34" Margin="112,9,0,0" VerticalAlignment="Top" Width="100" Click="OnRemove"/>
    </Grid>
</Window>

    public partial class MainWindow : Window
    {
        private ObservableCollection<MyItem> items = new ObservableCollection<MyItem>();
        private static Random seed; 

        public MainWindow()
        {
            this.InitializeComponent();

            seed = new Random();

            lbTest.ItemsSource = items;
        }

        private Color GetRandomColor() 
        { 
            Color newColor = new Color(); 

            newColor.A = (byte)255; 
            newColor.R = (byte)seed.Next(0, 256); 
            newColor.G = (byte)seed.Next(0, 256); 
            newColor.B = (byte)seed.Next(0, 256); 

            return newColor;
        }

        private void OnRemove(object sender, System.Windows.RoutedEventArgs e)
        {
            if (items.Count > 0)
                items.RemoveAt(items.Count - 1);
        }

        private void OnAdd(object sender, System.Windows.RoutedEventArgs e)
        {
            items.Add(new MyItem() { 
                Name = Guid.NewGuid().ToString(),
                MyColor = new SolidColorBrush(GetRandomColor())
            });
        }
    }

    public class MyItem
    {
        public string Name
        {
            get;
            set;
        }

        public Brush MyColor
        {
            get;
            set;
        }
    }