Vista - RelativeSource=/ParentData in Setter or Template?

When I access RelativeSource=/ParentData inside style Setters and Templates
I always get null. I can't work out how to rebind the DataContext in these
scenarios.

For example:

<Style x:Key="MyStyle" TargetType="{x:Type Control}">
<Setter Property="DataContext" Value="{Binding RelativeSource=/ParentData}"
/>
</Style>

or:

<Setter Property="Template">
<Setter.Value>
<ControlTemplate>
<Grid DataContext="{Binding RelativeSource=/ParentData}" />
</ControlTemplate>
</Setter.Value>
</Setter Property="Template">

How can I reference the current context? I'm trying to do this because I
need to run the current data context through an IValueConverter.

- Doug






A complete example follows, drop the DataContext Setter to see the desired
result.

<?Mapping XmlNamespace="sys" ClrNamespace="System" Assembly="mscorlib"?>
<Window x:Class="EventTest.Window1"
xmlns="http://schemas.microsoft.com/winfx/avalon/2005"
xmlns:x="http://schemas.microsoft.com/winfx/xaml/2005"
xmlns:sys="sys"
Title="EventTest"
>
<Window.Resources>
<x:ArrayExtension Type="{x:Type sys:String}" x:Key="Data">
<sys:String>one</sys:String>
<sys:String>two</sys:String>
<sys:String>three</sys:String>
<sys:String>four</sys:String>
</x:ArrayExtension>
<Style x:Key="MasterDetail" TargetType="{x:Type Control}">
<Setter Property="DataContext" Value="{Binding RelativeSource=/PreviousData}"
/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate>
<DockPanel>
<TextBlock TextBlock.FontSize="30" DockPanel.Dock="Right" Text="{Binding
Path=/.}" />
<ListBox ItemsSource="{Binding}" IsSynchronizedWithCurrentItem="True"
/>
</DockPanel>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Window.Resources>
<DockPanel DataContext="{Binding Source={StaticResource Data}}">
<Control Style="{StaticResource MasterDetail}" />
</DockPanel>
</Window>