UserControl content is empty when trying to use ContentPresenter inside DataTemplate - wpf

Question

I have a main abstract code-only class BaseImpostorButton, inheriting UserControl. I have a child class ClickableImageButton with xaml and code-behind.
I'm using the following style with ControlTemplate :
<Style TargetType="{x:Type local:ClickableImageButton}">
<Setter Property="ToolTipService.InitialShowDelay" Value="0"/>
<Setter Property="BorderThickness" Value="0"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type local:ClickableImageButton}">
<StackPanel Margin="{TemplateBinding Margin}" HorizontalAlignment="{TemplateBinding HorizontalAlignment}" VerticalAlignment="{TemplateBinding VerticalAlignment}">
<ContentPresenter
Content="{TemplateBinding Content}"
ContentTemplate="{TemplateBinding ContentTemplate}" />
</StackPanel>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
When using in a ListView as raw ListViewItem, my ClickableImageButton shows correctly.
BUT: when using it in a listview with ItemTemplate DataTemplate, the ClickableImageButton is no longer shown... as if the Content was empty when inside a DataTemplate.
The solution i found was to write a DependencyProperty ButtonContent on BaseImpostorButton and set it explicitly in xaml.
But can someone explain this issue ?
EDIT: Here are the 2 different xaml
The one that is correctly showing the underlying image (ClickableImage is an Image)
<ListView Grid.Row="1" Name="ListViewSections" ItemsSource="{Binding Path=Sections}" Background="{x:Null}" SizeChanged="ListViewSections_SizeChanged">
<ListViewItem>
<Grid MaxWidth="600">
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition MaxWidth="150"/>
<ColumnDefinition />
</Grid.ColumnDefinitions>
<TextBlock Grid.Row="0" Grid.ColumnSpan="2" Text="{Binding Path=Titre}" Margin="5,0,5,0" FontSize="18" FontWeight="Bold" Foreground="White" TextWrapping="Wrap" FontFamily="Arial" HorizontalAlignment="Left" />
<local:ClickableImageButton Grid.Row="1" Tag="{Binding Path=Id}" Grid.Column="0" ImpostorClick="Image_Click" Margin="10">
<local:ClickableImageButton.Content>
<local:ClickableImage Source="Content/tada.png" />
</local:ClickableImageButton.Content>
</local:ClickableImageButton>
<TextBlock Grid.Row="1" Grid.Column="1" Text="{Binding Path=Texte}" Margin="10,0,10,0" FontSize="16" Foreground="White" TextWrapping="Wrap" FontFamily="Arial" VerticalAlignment="Center" HorizontalAlignment="Left" />
</Grid>
</ListViewItem>
</ListView>
And the one that's not working
<ListView Grid.Row="1" Name="ListViewSections" ItemsSource="{Binding Path=Sections}" Background="{x:Null}" SizeChanged="ListViewSections_SizeChanged">
<ListView.ItemTemplate>
<DataTemplate>
<Grid MaxWidth="600">
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition MaxWidth="150"/>
<ColumnDefinition />
</Grid.ColumnDefinitions>
<TextBlock Grid.Row="0" Grid.ColumnSpan="2" Text="{Binding Path=Titre}" Margin="5,0,5,0" FontSize="18" FontWeight="Bold" Foreground="White" TextWrapping="Wrap" FontFamily="Arial" HorizontalAlignment="Left" />
<local:ClickableImageButton Grid.Row="1" Tag="{Binding Path=Id}" Grid.Column="0" ImpostorClick="Image_Click" Margin="10">
<local:ClickableImageButton.Content>
<local:ClickableImage Source="Content/tada.png" />
</local:ClickableImageButton.Content>
</local:ClickableImageButton>
<TextBlock Grid.Row="1" Grid.Column="1" Text="{Binding Path=Texte}" Margin="10,0,10,0" FontSize="16" Foreground="White" TextWrapping="Wrap" FontFamily="Arial" VerticalAlignment="Center" HorizontalAlignment="Left" />
</Grid>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>

Answer 1

So finally i get it to work. That wasn't due to the fact that i was deriving from UserControl.
So i kept deriving BaseImpostorButton from UserControl, i emptyed the ContentPresenter in the ControlTemplate (<ContentPresenter />).
I didn't have to set the DefaultStyleKey.
I just had to remove any content from the child class xaml file. Indeed, when i created my child UserControl, i didn't removed the default content added, that is <Grid />. Removing this just solved all my problems.
Looks like the default Content is not overriden when we try to set it from a templated context, but only when set from a non templated context.
ie Former code:
<sk:BaseImpostorButton x:Class="Compteur_3D.ClickableImageButton"
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"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="300">
<Grid/>
</sk:BaseImpostorButton>
revised code:
<sk:BaseImpostorButton x:Class="Compteur_3D.ClickableImageButton"
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" mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="300">
</sk:BaseImpostorButton>
Edit: At runtime, my ClickableImageButton element has the right content (ie ClickableImage) when the <Grid /> is removed. BUT when <Grid /> is not removed, my ClickableImageButton has the empty Grid as content... As if this <Grid /> was not overriden when setting the content in:
<local:ClickableImageButton ImpostorClick="Image_Click" Margin="10">
<local:ClickableImageButton.Content>
<local:ClickableImage Source="{Binding Path=Image.Source}" />
</local:ClickableImageButton.Content>
</local:ClickableImageButton>
Edit: Target Framework 4 Client Profile