As stated in the question below, Setters cannot contain Bindings in Windows RT/Phone 8.1
=> Binding SelectedItems in ListView to a ViewModel in Windows Phone 8.1
Has this changed in the new Universal Windows Applications?
Still not Bindings in values?
You can't bind to the DataContext using the normal ways, but you can do it using other (smart) methods:
See the below article - it provides a "helper" that allows to bind to the DataContext with a Setter.