wpf 如何从背后的代码访问数据模板中的控件？
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how to access a control within Data Template from code behind?
提问by Badrul
I have a MediaElementwithin the DataTemplatebut I am unable to access it from the code behind.
我有一个MediaElement，DataTemplate但我无法从后面的代码访问它。
I am posting XAML code below:
我在下面发布 XAML 代码：
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="605*"/>
<ColumnDefinition Width="151*"/>
</Grid.ColumnDefinitions>
<GroupBox Header="My Videos" Height="177" VerticalAlignment="Top" Margin="5,320,5,0" Grid.ColumnSpan="2">
<ListBox x:Name="VideoList" ItemsSource="{Binding Videos }" Width="auto" Height=" auto" Margin="0,0,0,0" Grid.ColumnSpan="2" >
<DataTemplate x:Name="DTVideos">
<ListBoxItem Name="lbivid1" BorderThickness="2" Width="240" Selected="lbivid_Selected" >
<MediaElement Name="vidList" Height="150" Width="150" Source="{Binding SourceUri}" Position="00:00:05" LoadedBehavior="Pause" ScrubbingEnabled="True"/>
</ListBoxItem>
</DataTemplate>
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel Orientation="Horizontal" Margin="0,0,0,0"/>
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
</ListBox>
</GroupBox>
<GroupBox Header="Preview" Height="320" Width="400" VerticalAlignment="Top" DockPanel.Dock="Left">
<MediaElement x:Name="videoPreview" HorizontalAlignment="Left" Height="300" VerticalAlignment="Top" Width="388"/>
</GroupBox>
</Grid>
Code behind:
后面的代码：
private void lbivid_Selected(object sender, RoutedEventArgs e)
{
imagePreview.Visibility = Visibility.Hidden;
string urlStr = (VidList.Source).ToString();
Uri temp = new Uri(UrlStr);
videoPreview.Source = temp;
}
Can anyone of you please tell me how can it be done?
你们中的任何人都可以告诉我怎么做吗？
回答by Sheridan
You shouldbe able to access your control using the FrameworkTemplate.FindNamemethod... first, get the ContentPresenterfrom one of the ListBoxItems:
您应该能够使用该FrameworkTemplate.FindName方法访问您的控件...首先，ContentPresenter从以下其中一个获取ListBoxItem：
ContentPresenter contentPresenter = FindVisualChild<ContentPresenter>(yourListBoxItem);
Then get the DataTemplatefrom the ContentPresenter:
然后DataTemplate从ContentPresenter：
DataTemplate yourDataTemplate = contentPresenter.ContentTemplate;
Then get the MediaElementfrom the DataTemplate:
然后MediaElement从DataTemplate：
MediaElement yourMediaElement = yourDataTemplate.FindName("vidList", contentPresenter)
as MediaElement;
if (yourMediaElement != null)
{
// Do something with yourMediaElement here
}
Please see the FrameworkTemplate.FindNameMethodpage on MSDN for more information.
有关详细信息，请参阅MSDN 上的FrameworkTemplate.FindName方法页面。
回答by Pavel Tupitsyn
You have sender in your event handler, which is ListBoxItem, and MediaElement is ListBoxItem.Content
您的事件处理程序中有发送者，即 ListBoxItem，MediaElement 是 ListBoxItem.Content
var mediaElement = ((ListBoxItem)sender).Content as MediaElement;
if (mediaElement != null) ...
