獲取由DataTemplate實例化的對象的父對象

Question

我的DataTemplate中有帶UserControl的ListView：

<ListView ItemSource="{Binding MyCollection}" x:Name="MyListView">
    <ListView.ItemTemplate>
        <DataTemplate>
            <MyUserControl Loaded="OnLoaded" Content="{Binding MyProperty}"/>
        </DataTemplate>
    </ListView.ItemTemplate>
</ListView>

當我嘗試在MyUserControl的代碼中獲取父級ListView時（通過不同方式）：

private void OnLoaded(object sender, RoutedEventArgs e)
{
    var parent1 = Parent;
    var parent2 = VisualTreeHelper.GetParent(this);
    var parent3 = FindName("MyListView");
    var parent4 = DataContext;
}

parent1為null，parent2為ListViewItemPresenter，parent3也為null，parent4是我的ViewModel類（MyCollection所在）。

如何獲得實際的ListView？

Answer 1

從UWPCommunityToolkit嘗試這些VisualTreeExtensions

若要從ListView.ItemTemplate （ DataTemplate ）獲取父ListView ，請使用FindVisualAscendant方法

    /// <summary>
    /// Find first ascendant control of a specified type.
    /// </summary>
    /// <typeparam name="T">Type to search for.</typeparam>
    /// <param name="element">Child element.</param>
    /// <returns>Ascendant control or null if not found.</returns>
    public static T FindAscendant<T>(this FrameworkElement element)
        where T : FrameworkElement
    {
        if (element.Parent == null)
        {
            return null;
        }

        if (element.Parent is T)
        {
            return element.Parent as T;
        }

        return (element.Parent as FrameworkElement).FindAscendant<T>();
    }

    /// <summary>
    /// Find first visual ascendant control of a specified type.
    /// </summary>
    /// <typeparam name="T">Type to search for.</typeparam>
    /// <param name="element">Child element.</param>
    /// <returns>Ascendant control or null if not found.</returns>
    public static T FindVisualAscendant<T>(this FrameworkElement element)
        where T : FrameworkElement
    {
        var parent = VisualTreeHelper.GetParent(element);

        if (parent == null)
        {
            return null;
        }

        if (parent is T)
        {
            return parent as T;
        }

        return (parent as FrameworkElement).FindVisualAscendant<T>();
    }