如何使EntranceThemeTransition工作在自定义面板和放大器;的ItemsSource？ [英] How to make EntranceThemeTransition works on a Custom Panel & ItemsSource?

问题描述

我不能让EntranceThemeTransition到自定义面板ItemsPanelTemplate上工作。参见：

I can't get EntranceThemeTransition to work on a custom panel as ItemsPanelTemplate. See:

背后最简单的代码：

public List<int> MyListExample = new List<int>() {0, 1, 2, 3, 4, 5};

最简单的XAML：

Simplest XAML:

<ListView Width="120" ItemsSource="{x:Bind MyListExample}">
    <ListView.ItemContainerTransitions>
        <TransitionCollection>
            <EntranceThemeTransition FromVerticalOffset="200" IsStaggeringEnabled="True"/>
        </TransitionCollection>
    </ListView.ItemContainerTransitions>

    <ListView.ItemsPanel>
        <ItemsPanelTemplate>
            <!--EntranceThemeTransition WORKS-->
            <ItemsWrapGrid/>

            <!--EntranceThemeTransition does NOT work-->
            <!--<StackPanel/>-->

            <!--EntranceThemeTransition does NOT work. goal: make this work-->
            <!--<local:FluidPanel/>-->
        </ItemsPanelTemplate>
    </ListView.ItemsPanel>
</ListView>

不知道如何使动画作品？

Any idea how to make the animation works?

PS：我把的Debug.WriteLine上Loaded事件，它被称为两次，我不知道为什么。这可能会引起问题，因为这部动画时才会触发一次。添加的的ItemsSource之前可能被触发。

PS: I put a Debug.WriteLine on the Loaded event, it's being called twice and I have no idea why. This might be causing the problem, because this animation is only triggered once. Possibly is being triggered before the ItemsSource being added.

PS2：它只使用的ItemsSource时发生。如果我直接添加元素上的ListView XAML它显示的动画。

PS2: It only happens when using ItemsSource. If I add the elements directly on the ListView XAML it shows the animation.

（也的 MSDN ）

推荐答案

这实在是一个错误。结合被动画后一起应用或而已。因为EntranceThemeTransition只发生一次，它认为它已经执行，并禁用它。

It is really a bug. The binding gets applied together or just after the animation. Because EntranceThemeTransition just happens once, it thinks that it already executed and disables it.

这是我目前使用的解决方法：

This is the workaround I'm currently using:

C＃：

public ObservableCollection<int> items { get; set; } = new ObservableCollection<int>() { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };

private async void MyListView_Loaded(object sender, RoutedEventArgs e)
{
    foreach (var item in items)
        MyListView.Items.Add(item);

    await Task.Delay(1000); //wait for animation
    MyListView.SetBinding(ItemsControl.ItemsSourceProperty, new Binding() { Source = this, Path = new PropertyPath("items"), Mode = BindingMode.TwoWay });
}

XAML：

XAML:

<ListView x:Name="MyListView" Loaded="MyListView_Loaded">
    <ListView.ItemContainerTransitions>
        <TransitionCollection>
            <EntranceThemeTransition FromHorizontalOffset="0" FromVerticalOffset="2000" IsStaggeringEnabled="True"/>
        </TransitionCollection>
    </ListView.ItemContainerTransitions>

    <ListView.ItemsPanel>
        <ItemsPanelTemplate>
            <StackPanel/>
        </ItemsPanelTemplate>
    </ListView.ItemsPanel>
</ListView>

感谢富兰克林陈上的有关添加的项目上后面的代码MSDN论坛。

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