Why does a String DataTemplate cause a stack overflow exception? - wpf

Question

I have a couple of DataTemplates defined in the resources of a ContentControl:
<DataTemplate DataType="{x:Type sys:String}">
<Label Content="{Binding}" HorizontalContentAlignment="Center" />
</DataTemplate>
<DataTemplate DataType="{x:Type dmodels:CBClient}"> <!-- Client Details Template -->
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<TextBlock Grid.Column="0" Text="Client Details" Background="{StaticResource brush_Client}" Foreground="White" Margin="0,0,1,0" VerticalAlignment="Center" />
<TextBlock Grid.Column="1" Text="Id:" Background="{StaticResource brush_Client}" Foreground="White" />
<TextBlock Grid.Column="2" Text="{Binding Path=ClientId}" Background="{StaticResource brush_Client}" Foreground="White" Margin="0,0,1,0" />
<Button Grid.Column="3" Style="{StaticResource EditButton}" />
</Grid>
</DataTemplate>
If I return a CBClient object, I get the proper display from the defined DataTemplate.
If I return a string, I get a StackOverflowException.
If I eliminate the String DataTemplate and return a string, I get the string displayed, but not formatted as I want it.
What am I doing wrong? Do I have to wrap the basic string return into a full class, and expose a message property? Is there no way to combine complex objects with integral types for DataTemplates?
Thanks.
J

Answer 1

You introduced a complication by using a Label. It automatically generates a textblock if you bind to a string. Binding in that way has an odd effect if you rely on it automatically adding the textblock. I should think it's because it sees an object rather than a string from the type of the property you're binding.
You could just do:
<DataTemplate DataType="{x:Type sys:String}">
<Label HorizontalContentAlignment="Center">
<TextBlock Text="{Binding}" />
</Label>
</DataTemplate>