Overriding Style of WPF TreeView Items - wpf

Question

I am using the awesome MahAppsMetro WPF control suite. I have a tree view that loads the file system. I also want to display images in the TreeViewItems so I have overridden the metro tree style as follows
<UserControl x:Class="GDE.Tree.TreeView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:Caliburn="http://www.caliburnproject.org"
xmlns:Metro="http://metro.mahapps.com/winfx/xaml/controls"
mc:Ignorable="d"
d:DesignHeight="300"
d:DesignWidth="300">
<UserControl.Resources>
<HierarchicalDataTemplate x:Key="TreeTemplate" ItemsSource="{Binding Path=Children}"/>
</UserControl.Resources>
<!--TreeView-->
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<TextBox Grid.Row="0"
Margin="5"
IsReadOnly="True"
Text="{Binding SelectedPath, Mode=TwoWay}"/>
<TreeView Grid.Row="1"
Margin="5"
ItemsSource="{Binding RootChildren}"
ItemTemplate="{StaticResource TreeTemplate}">
<TreeView.Resources>
<Style TargetType="{x:Type TreeViewItem}"
BasedOn="{StaticResource MetroTreeViewItem}">
<Setter Property="HeaderTemplate">
<Setter.Value>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<Image Name="img"
Width="16"
Height="16"
Stretch="Fill"
Source="{Binding Path=Icon, Mode=OneTime}"
VerticalAlignment="Center"
HorizontalAlignment="Center"/>
<TextBlock Text="{Binding DisplayName, Mode=OneTime}"
Margin="5,0,0,0"
VerticalAlignment="Center"
HorizontalAlignment="Left"/>
</StackPanel>
</DataTemplate>
</Setter.Value>
</Setter>
</Style>
</TreeView.Resources>
</TreeView>
</Grid>
</UserControl>
But this does not seem to work as intended and I can't figure out why. From this XAML, I get no binding errors and the visuals look like:
I have gone more extensive with the XAML mark up but I am getting the exact same visuals. How can I change the above XAML to give me the Image/TextBlocks as well as the MahApps look and feel?
Thanks for your time.

Answer 1

To sum up comments instead of changing Style you need to move StackPanel from DataTemplate directly into HierarchicalDataTemplate as at the moment used template has no content:
<HierarchicalDataTemplate x:Key="TreeTemplate" ItemsSource="{Binding Path=Children}">
<StackPanel Orientation="Horizontal">
<Image Name="img" ... />
<TextBlock Text="{Binding DisplayName, Mode=OneTime}" ... />
</StackPanel>
</HierarchicalDataTemplate>