DataTemplate with TextBlock, ContentControl.ContentStringFormat is ignored - wpf

Question

I have the following datatemplate
<DataTemplate x:Key="SectionHeader">
<Border CornerRadius="5">
<Border.Background>
<LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
<GradientStop Color="#FF1E5270" Offset="1"/>
<GradientStop Color="#FF3E7595"/>
</LinearGradientBrush>
</Border.Background>
<TextBlock Text="{Binding}" FontSize="14" Foreground="White" Padding="0,5" HorizontalAlignment="Center" FontWeight="Bold" />
</Border>
</DataTemplate>
and I can use it as follows
<ContentControl Content="Summary" ContentTemplate="{StaticResource SectionHeader}" />
This works fine. But when I try to do the following
<ContentControl Content="{Binding SelectedOrder}" ContentStringFormat="Details for Order \{0\}" ContentTemplate="{StaticResource SectionHeader}" />
I do not get the the full string only the order number.
Is there a way to make this work with a single datatemplate or do I need to create a second data template?

Answer 1

See MSDN documentation on ContentControl.ContentStringFormat:
If you set the ContentTemplate or ContentTemplateSelector property of a ContentControl, the ContentStringFormat property is ignored.
Instead of relying on ContentStringFormat, you should either add StringFormat to your binding or create a trivial StringFormatConverter : IValueConverter and set binding's Converter and ConverterParameter properties, in case Binding.StringFormat doesn't work (it has non-obvious limitations too — it's used only when target property is of type String).
For example:
<Control.Resources>
<a:StringFormatConverter x:Key="StringFormatConverter"/>
</Control.Resources>
<!-- ... -->
<ContentControl
Content="{Binding SelectedOrder,
Converter={StaticResource StringFormatConverter},
ConverterParameter='Details for Order {0}'}"
ContentTemplate="{StaticResource SectionHeader}"/>
You can use this implementation of StringFormatConverter.