WPF won't let me put a binding on the path of a binding -- is there another way?

Question

I have a DataTemplate that I'm using as the CellTemplate for a GridViewColumn.

I want to write something like this for the DataTemplate:

<DataTemplate
    x:Key="_myTemplate">
    <TextBlock
        Text="{Binding Path={Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type GridViewColumn}}, Path=Header}}" />
</DataTemplate>

My GridView is bound to a DataTable, and I want to bind to the column of the DataTable whose name is equal to the Header of the GridViewColumn the DataTemplate is attached to. [I hope that made sense!]

Unfortunately, this doesn't work. I get a XamlParseException: "A 'Binding' cannot be set on the 'Path' property of type 'Binding'. A 'Binding' can only be set on a DependencyProperty of a DependenceyObject."

How can I set this up?

Edit (elevating comment by DanTheMan to the question)

I basically need a DataTemplate whose binding is determined by the DataContext and which column the DataTemplate is attached to. Is there an alternative?

Answer 1

You cannot assign a Binding to just any property. The property must either of the type Binding or be implemented as a Dependency Property on the object.

The Path property of the Binding class is of type PropertyPath and Binding does not implement the Path property as a dependency property. Hence you cannot dynamically bind the Path in the way you are attempting to.

Edit

You basically want to embed metadata in your bound data which drives the configuration of the DataTemplate. This can't be done in XAML alone. You would need at least some support from code.

It would seem to me that the best approach would be to use a ViewModel. That makes the binding in the XAML straight-forward and pushes this "what to bind with what" decision down into the code of the ViewModel.

Answer 2

Don't you just want this?

{Binding Path=Header, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type GridViewColumn}}}