c# - 如何在 FlipView 中访问 DataTemplate 中的 xaml 控件

Question

我想访问 C# 代码中的“图像”元素。我知道我不能直接访问它，因为它在数据模板中。我已经尝试过视觉树，但仍然无法在代码中获得“图像”控制元素。

<FlipView
            x:Name="flipView"
            AutomationProperties.AutomationId="ItemsFlipView"
            AutomationProperties.Name="Item Details"
            TabIndex="1"
            Grid.RowSpan="2"
            ItemsSource="{Binding Source={StaticResource itemsViewSource}}" SelectionChanged="flipView_SelectionChanged">

            <FlipView.ItemContainerStyle>
                <Style TargetType="FlipViewItem">
                    <Setter Property="Margin" Value="0,137,0,0"/>
                </Style>
            </FlipView.ItemContainerStyle>

            <FlipView.ItemTemplate>
                <DataTemplate>

                    <!--
                        UserControl chosen as the templated item because it supports visual state management
                        Loaded/unloaded events explicitly subscribe to view state updates from the page
                    -->
                    <UserControl Loaded="StartLayoutUpdates" Unloaded="StopLayoutUpdates">
                        <ScrollViewer x:Name="scrollViewer" Style="{StaticResource HorizontalScrollViewerStyle}" Grid.Row="1">

                            <!-- Content is allowed to flow across as many columns as needed -->
                            <common:RichTextColumns x:Name="richTextColumns" Margin="117,0,117,47">
                                <RichTextBlock x:Name="richTextBlock" Width="560" Style="{StaticResource ItemRichTextStyle}" IsTextSelectionEnabled="False">
                                    <Paragraph>
                                        <Run FontSize="26.667" FontWeight="Light" Text="{Binding Title}"/>
                                        <LineBreak/>
                                        <LineBreak/>
                                        <Run FontWeight="Normal" Text="{Binding Subtitle}"/>
                                    </Paragraph>
                                    <Paragraph LineStackingStrategy="MaxHeight">
                                        <InlineUIContainer>
                                            <Image x:Name="image" MaxHeight="480" Margin="0,20,0,10" Stretch="Uniform" Source="{Binding Image}" AutomationProperties.Name="{Binding Title}"/>
                                        </InlineUIContainer>
                                    </Paragraph>                                  
                                </RichTextBlock>
                            </common:RichTextColumns>
                        </ScrollViewer>
                    </UserControl>
                </DataTemplate>
            </FlipView.ItemTemplate>
</FlipView>

Answer 1

我已经尝试过，并且能够按照您的描述访问 FlipView DataTemplate 内部的控件。尝试以下方法，如果有帮助请告诉我。

public static IEnumerable<T> RecurseChildren<T>(DependencyObject root) where T : UIElement
{
    if (root is T)
    {
        yield return root as T;
    }

    if (root != null)
    {
        var count = VisualTreeHelper.GetChildrenCount(root);


        for (var idx = 0; idx < count; idx++)
        {
            foreach (var child in RecurseChildren<T>(VisualTreeHelper.GetChild(root, idx)))
            {
                yield return child;
            }
        }
    }
}

访问图像控件:

var imageControl = RecurseChildren<Image>(rootVisual).FirstOrDefault();

这里的 rootVisual 是我页面中的 Grid 实例。