如何为ItemsControl内部元素绑定上层按钮作为动画触发源？

问题原因 #

你遇到的名称查找失败是因为DataTemplate属于独立的XAML名称范围，模板内部的SourceName只能查找同个模板内的控件，无法访问到ItemsControl外定义的PlayButton。

解决方案 #

方案1：快速修复（仅修改一行XAML） #

直接用x:Reference突破名称范围限制，替换原来的SourceName即可：

<!-- 把原来的EventTrigger行替换成下面的 -->
<EventTrigger RoutedEvent="Button.Click" Source="{x:Reference PlayButton}">

如果要加停止功能，再新增一个对应Stop按钮的触发器即可，记得给原有BeginStoryboard加x:Name="CircleAnimBegin"关联停止操作：

<EventTrigger RoutedEvent="Button.Click" Source="{x:Reference StopButton}">
    <StopStoryboard BeginStoryboardName="CircleAnimBegin"/>
</EventTrigger>

方案2：严格遵循MVVM（推荐） #

这种方式完全移除视图的硬编码依赖，用ViewModel属性驱动动画：

1. 修改ParentViewModel

新增播放状态属性和操作命令：

public class ParentViewModel : BindableBase
{
    private bool _isPlaying;
    public bool IsPlaying
    {
        get => _isPlaying;
        set => SetProperty(ref _isPlaying, value);
    }

    public DelegateCommand PlayCommand { get; }
    public DelegateCommand StopCommand { get; }

    private List<MyCircle> myItemsModel;
    public List<MyCircle> MyItemsModel
    {
        get => myItemsModel;
        set => SetProperty(ref myItemsModel, value);
    }

    public ParentViewModel()
    {
        PlayCommand = new DelegateCommand(() => IsPlaying = true);
        StopCommand = new DelegateCommand(() => IsPlaying = false);
        // 保留原有实例化MyItemsModel的逻辑
    }
}

2. 修改XAML绑定

首先替换按钮的Click事件为命令绑定：

<Button Content="Play" Grid.Row="0" Grid.Column="1" Command="{Binding PlayCommand}"/>
<Button Content="Stop" Grid.Row="1" Grid.Column="1" Command="{Binding StopCommand}"/>

然后把DataTemplate里的EventTrigger换成DataTrigger，通过RelativeSource绑定到父级ViewModel的IsPlaying属性：

<Path Fill="Red" x:Name="ClockwiseBobbinsPath">
    <Path.Data>
        <EllipseGeometry x:Name="MyCircle" RadiusX="5" RadiusY="5"/>
    </Path.Data>
    <Path.Style>
        <Style TargetType="Path">
            <Style.Triggers>
                <DataTrigger Binding="{Binding DataContext.IsPlaying, RelativeSource={RelativeSource AncestorType=ItemsControl}}" Value="True">
                    <DataTrigger.EnterActions>
                        <BeginStoryboard x:Name="CircleAnimBegin">
                            <Storyboard>
                                <PointAnimationUsingPath
                                    Storyboard.TargetProperty="Data.Center"
                                    Duration="0:0:10"
                                    RepeatBehavior="Forever">
                                    <PointAnimationUsingPath.PathGeometry>
                                        <PathGeometry 
                                            Figures="{Binding AnimationPath}"
                                            PresentationOptions:Freeze="True" />
                                    </PointAnimationUsingPath.PathGeometry>
                                </PointAnimationUsingPath>
                            </Storyboard>
                        </BeginStoryboard>
                    </DataTrigger.EnterActions>
                    <DataTrigger.ExitActions>
                        <StopStoryboard BeginStoryboardName="CircleAnimBegin"/>
                    </DataTrigger.ExitActions>
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </Path.Style>
</Path>

这里移除了Storyboard.TargetName，改为直接绑定Data.Center属性，避免额外的名称查找问题。

内容的提问来源于stack exchange，提问作者Yose