Find a Wpf Element Inside Datatemplate in the Code-Behind

Find a WPF element inside DataTemplate in the code-behind

I use this function a lot in my WPF programs to find children elements:

public IEnumerable<T> FindVisualChildren<T>(DependencyObject depObj) where T : DependencyObject
{
   if (depObj != null)
   {
       for (int i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++)
       {
           DependencyObject child = VisualTreeHelper.GetChild(depObj, i);

           if (child != null && child is T)
               yield return (T)child;

           foreach (T childOfChild in FindVisualChildren<T>(child))
               yield return childOfChild;
       }
   }
}

Usage:

foreach (var rectangle in FindVisualChildren<Rectangle>(this))
{
  if (rectangle.Name == "rectangleBarChart")
  {
    /*   Your code here  */
  }
}

How to get element in code behind from DataTemplate

So here is a working solution:

public void TestMethod()
{
    DataTemplate dt = FlipView5Horizontal.ItemTemplate;
    DependencyObject dio = dt.LoadContent();
    foreach (var timeLine in FindVisualChildren<TextBlock>(dio)) //FindVisualTree is defined in the question :)
    {
        if (timeLine.Name == "xxxTB")
        { }
    }
}

Now, I am able to load the control at least. (However, I read that this trick should not be used in the overridden method OnApplyTemplate for some reason).

C# - WPF Access elements in a DataTemplate from code behind

Here is your answer Calling Storyboard inside DataTemplate.

But keep in mind that doing that is not a good idea. Accessing any UI Element from your code behind is not a great idea, because it creates a tight coupling between your code and your UI.

I would suggest you to use MVVM instead, and to bind a boolean to run your storyboard as explained here: How to play Storyboard in ViewModel?

Access XAML Control In DataTemplate From CodeBehind?

I would normally recommend not to touch UIElements from code... but the MediaElement is a special case... maybe you should wrap the whole template inside a usercontrol (maybe with some custom DepProps) and that will give you better control over the whole thing.

Edit: Another approach would be to create a Behavior with a couple of properties (such as IsPlaying) and manipulate the mediaelement from there. Then you could use this behavior in the XAML of the DataTemplate, with no need for code behind or usercontrols.

Access an element from DataTemplate

You should not use ContentControl try using ContentPresent

<Grid x:Name="MyGrid">
    <ContentPresenter x:Name="ContentControl" Content="{Binding}" Style="{StaticResource MyContentControlStyle}" />
</Grid>

And behind the code you have to explicitly have to say apply template in order to get it

ContentControl.ApplyTemplate();
var dataGrid = ContentControl.ContentTemplate.FindName("dataGridFromDataTemplate", ContentControl) as DataGrid;

how to access a control within Data Template from code behind?

You should be able to access your control using the FrameworkTemplate.FindName method... first, get the ContentPresenter from one of the ListBoxItems:

ContentPresenter contentPresenter = FindVisualChild<ContentPresenter>(yourListBoxItem);

Then get the DataTemplate from the ContentPresenter:

DataTemplate yourDataTemplate = contentPresenter.ContentTemplate;

Then get the MediaElement from the DataTemplate:

MediaElement yourMediaElement = yourDataTemplate.FindName("vidList", contentPresenter) 
as MediaElement;
if (yourMediaElement != null)
{
    // Do something with yourMediaElement here
}

Please see the FrameworkTemplate.FindName Method page on MSDN for more information.

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