Is there a cleaner way to bind a property to the owner of a DataContext?

Question

I have a code that looks like this:

<Expander Header="{Binding SelectedSlot.Name}"
          Visibility="{Binding ShowGroupSlot, Converter={StaticResource BooleanToVisibility}}">
    <Controls:GroupPrototypeSlotControl Slot="{Binding DataContext.SelectedSlot, 
        RelativeSource={RelativeSource Mode=FindAncestor,  AncestorType={x:Type Expander}}}" />
</Expander>

It works, but the ugliness of Slot Binding bothers me. This is necessary because GroupPrototypeSlotControl has a GroupPrototypeViewModel as its DataContext. If I just use it {Binding SelectedSlot}, it tries to resolve it on the "child" ViewModel, which fails. I wrap this around explicitly looking at the DataContext of my parent control. Is there a cleaner way to do this type of binding?

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EDIT: I found a cleaner way to solve my problem, although it still looks like a hack. I modified GroupPrototypeSlotControl so that in this case there is a top-level LayoutRoot (in this case, StackPanel), and then set the DataContext LayoutRoot to ViewModel, and not set the DataContext for the entire control. This allows me to use the syntax {Binding SelectedSlot}where I use the control (since the control still has a parent DataContext), due to a slight increase in the complexity of the control. In general, this is probably the best template for a custom control, since the consumer of the control expects {Binding} to be resolved to their parent DataContext if it is not explicitly specified.

Answer 1

( ) - ElementName Binding :

<Expander Header="{Binding SelectedSlot.Name}"
          x:Name="expander"
          Visibility="{Binding ShowGroupSlot, Converter={StaticResource BooleanToVisibility}}">
    <Controls:GroupPrototypeSlotControl Slot="{Binding DataContext.SelectedSlot, ElementName=expander}" />
</Expander>