TemplateBinding as InvokeCommandAction CommandParameter not working? - wpf

Question

I'm trying to write a reusable template for a control I want to use several times in my window. In it I have some commands with CommandParameter. The CommandParameter is an object I want to pass via the "Tag" property of this template.
For the "MenuItem" CommandParameter and the StackPanel "DataContext" this is working just fine. But for the "MouseDown" event (or "PreviewMouseDown", I tried both) via InvokeCommandAction I'm only getting a null as parameter. It is firing the command and calls the right method, but the parameter is always null.
Here my Xaml (shortend):
<Window.Resources>
<ControlTemplate x:Key="FavControl" TargetType="ContentControl">
<StackPanel>
<StackPanel.ContextMenu>
<ContextMenu IsEnabled="{Binding FavContextMenuEnabled}">
<MenuItem Header="Bearbeiten"
Command="{Binding FavContextMenuEditCmd}"
CommandParameter="{TemplateBinding Tag}" />
<MenuItem Header="Löschen"
Command="{Binding FavContextMenuDeleteCmd}"
CommandParameter="{TemplateBinding Tag}" />
<Separator IsEnabled="{Binding UserisDev}" />
<MenuItem Header="Entwicklung"
Command="{Binding FavContextMenuStartDevCmd}"
CommandParameter="{TemplateBinding Tag}"
IsEnabled="{Binding UserisDev}" />
<MenuItem Header="Starte Objekt"
Command="{Binding FavContextMenuRunObjectCmd}"
CommandParameter="{TemplateBinding Tag}"
IsEnabled="{Binding UserisDev}" />
</ContextMenu>
</StackPanel.ContextMenu>
<i:Interaction.Triggers>
<i:EventTrigger EventName="MouseDown">
<i:InvokeCommandAction Command="{Binding FavoriteClickCmd}" CommandParameter="{TemplateBinding Tag}" />
</i:EventTrigger>
</i:Interaction.Triggers>
<StackPanel Orientation="Vertical" DataContext="{TemplateBinding Tag}">
<Image Source="{Binding FavImage, UpdateSourceTrigger=PropertyChanged,Mode=OneWay}"
HorizontalAlignment="Center" VerticalAlignment="Center" Height="70" Width="70" />
<TextBlock Text="{Binding Description}" HorizontalAlignment="Center" />
</StackPanel>
</StackPanel>
</ControlTemplate>
</Window.Resources>
<!-- ... -->
<ContentControl Grid.Row="0" Grid.Column="0" Template="{StaticResource FavControl}" Tag="{Binding FavoriteArray[0]}" />
<ContentControl Grid.Row="0" Grid.Column="1" Template="{StaticResource FavControl}" Tag="{Binding FavoriteArray[1]}" />
<ContentControl Grid.Row="0" Grid.Column="2" Template="{StaticResource FavControl}" Tag="{Binding FavoriteArray[2]}" />
<!-- ... -->
I need this parameter in the code behind method to know which object to work with. So, how can I pass this object? Why is the TemplateBinding not working? Can anybody tell me, what I'm doing wrong?
P.S.: Sorry for errors, english is not my native language :)

Answer 1

Instead of TemplateBinding, use a RelativeSource binding to TemplatedParent.
<b:InvokeCommandAction Command="{Binding FavoriteClickCmd}"
CommandParameter="{Binding Tag, RelativeSource={RelativeSource TemplatedParent}}" />