8

我有一个 MediaElement，它位于 Flipview 的数据模板中，我想在后面的代码中访问名为“video”的 MediaElement，以便我可以通过按钮分配播放、暂停等属性，这是我的代码试图做：

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

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

    <FlipView.ItemTemplate>
        <DataTemplate>
            <UserControl Loaded="StartLayoutUpdates" Unloaded="StopLayoutUpdates">
                <ScrollViewer x:Name="scrollViewer" Style="{StaticResource VerticalScrollViewerStyle}" Grid.Row="1">
                    <Grid Margin="120,0,20,20">
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition Width="400" />
                            <ColumnDefinition Width="40" />
                            <ColumnDefinition Width="360" />
                            <ColumnDefinition Width="40" />
                            <ColumnDefinition />
                        </Grid.ColumnDefinitions>
                        <Border BorderBrush="Black" BorderThickness="1" Width="350" HorizontalAlignment="Left" Grid.Row="0">
                            <MediaElement x:Name="Video" AutomationProperties.Name="Video" Source="/Assets/Big_Buck_Bunny.mp4" HorizontalAlignment="Center" VerticalAlignment="Stretch" Height="250" Width="350" AutoPlay="True" IsLooping="True" />
                        </Border>
                        <Border BorderBrush="Black" BorderThickness="1" Height="65" Width="350" HorizontalAlignment="Left" Grid.Row="1">
                            <StackPanel Orientation="Horizontal" HorizontalAlignment="Center" VerticalAlignment="Center">
                                <Button x:Name="playButton" Margin="0,0" Click="playButton_Click" Style="{StaticResource PlayAppBarButtonStyle}" HorizontalAlignment="Center" VerticalAlignment="Center"/>
                                <Button x:Name="pauseButton" Margin="0,0" Click="pauseButton_Click" Style="{StaticResource PauseAppBarButtonStyle}" HorizontalAlignment="Center" VerticalAlignment="Center"/>
                            </StackPanel>
                        </Border>
                    </Grid>
                </ScrollViewer>
            </UserControl>
        </DataTemplate>
    </FlipView.ItemTemplate>
</FlipView>

我如何达到预期目的？

4

3 回答 3

20

尝试以下操作：

    private DependencyObject FindChildControl<T>(DependencyObject control, string ctrlName)
    {
        int childNumber = VisualTreeHelper.GetChildrenCount(control);
        for (int i = 0; i < childNumber; i++)
        {
            DependencyObject child = VisualTreeHelper.GetChild(control, i);
            FrameworkElement fe = child as FrameworkElement;
            // Not a framework element or is null
            if (fe == null) return null;

            if (child is T && fe.Name == ctrlName)
            {
                // Found the control so return
                return child;
            }
            else
            {
                // Not found it - search children
                DependencyObject nextLevel = FindChildControl<T>(child, ctrlName);
                if (nextLevel != null)
                    return nextLevel;
            }
        }
        return null;
    }

然后从播放/暂停按钮按钮调用它：

    MediaElement media = FindChildControl<MediaElement>(this, "media") as MediaElement;
    media.Play();

关于该主题的相关博客文章

于 2013-03-03T21:57:27.410 回答
1

大约一年前，我写了一篇关于这个主题的博客文章。也许它会帮助你：http ://blog.jerrynixon.com/2012/09/how-to-access-named-control-inside-xaml.html

要点是这样的。您必须通过可视化树进行解析以获取所有元素，然后您可以使用 LINQ 之类的东西来过滤结果并获取您的对象。

于 2013-03-03T22:48:34.920 回答
0

我将 Jerry 的解决方案扩展为更灵活、性能更好的解决方案，只获得所需的控件，并且在递归调用期间不创建中间列表。

您可以像这样简单地使用来获得控制权：

var myControl = AllChildren(parent, c => c.Name == "xxx").FirstOrDefault();

为此，您应该包括以下 AllChildren 功能：

 private List<Control> AllChildren(DependencyObject parent, Func<DependencyObject, bool> query,   List<Control> _List = null ) 
    {
        if (_List == null)
             _List = new List<Control>();

        for (int i = 0; i < VisualTreeHelper.GetChildrenCount(parent); i++)
        {
            var _Child = VisualTreeHelper.GetChild(parent, i);
            if (_Child is Control && query(_Child))
            {

                _List.Add(_Child as Control);
            }
            AllChildren(_Child, query, _List);
        }
        return _List;
    }
于 2017-01-01T15:46:43.773 回答