Bind to a TemplatedParent's name in WPF? - wpf

Question

I'm trying to create a WPF Custom Control which will bind itself to it's templated parent's x:Name property. The code which I believe should do this which was also generated by the Binding Maker in Visual Studio, is as follows:
Binding RelativeSource={RelativeSource TemplatedParent}, Path=Name, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay
But this produces no result. I can replace the binding with any plain text and the desired behavior (the text overlays itself on the control when and only when the user has typed nothing into the control), but my goal here is to make this work as a sort of tooltip so the user knows what the field is supposed to be (as defined in the field's x:Name property).
Here's my full xaml:
<ResourceDictionary
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:SuperTB">
<Style TargetType="{x:Type local:SuperTextB}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type local:SuperTextB}">
<Border Background="{TemplateBinding Background}"
BorderBrush="{TemplateBinding BorderBrush}"
BorderThickness="{TemplateBinding BorderThickness}">
<TextBox Text="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=Text, Mode=TwoWay, UpdateSourceTrigger=LostFocus}">
<TextBox.Style>
<Style TargetType="TextBox">
<Style.Triggers>
<Trigger Property="Text" Value="">
<Setter Property="Background">
<Setter.Value>
<VisualBrush Stretch="None">
<VisualBrush.Visual>
<TextBlock Foreground="Gray" FontSize="24" Text="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=IsRequired}"></TextBlock>
</VisualBrush.Visual>
</VisualBrush>
</Setter.Value>
</Setter>
</Trigger>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=IsRequired}" Value="True">
<Setter Property="BorderThickness" Value="4" />
</DataTrigger>
</Style.Triggers>
</Style>
</TextBox.Style>
</TextBox>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
And the control's c#:
public class SuperTextB : Control
{
static SuperTextB()
{
DefaultStyleKeyProperty.OverrideMetadata(typeof(SuperTextB), new FrameworkPropertyMetadata(typeof(SuperTextB)));
}
public static DependencyProperty TextProperty = DependencyProperty.Register("Text", typeof(String), typeof(SuperTextB));
public string Text
{
get { return (String)GetValue(TextProperty); }
set { SetValue(TextProperty, value); }
}
private static DependencyProperty myNameProperty =
DependencyProperty.Register("MyName", typeof(string), typeof(SuperTextB), new PropertyMetadata("Unicorns !", NameChanged));
private static void NameChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
}
public string MyName
{
get { return (string)GetValue(myNameProperty); }
set { SetValue(myNameProperty, value); }
}
DependencyProperty isRequiredProperty =
DependencyProperty.Register("IsRequired", typeof(bool), typeof(SuperTextB), new PropertyMetadata(false, IsReqChanged));
private static void IsReqChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
}
public bool IsRequired
{
get { return (bool)GetValue(isRequiredProperty); }
set { SetValue(isRequiredProperty, value); }
}
}