WPF Show data from multiple DataContexts in ToolTip of ItemsControl

Question

I am trying to display a tooltip for an item generated by an ItemsControl that needs to pull data from conceptually unrelated sources. For example, say I have a

Answer 1

Second attempt

Ok, the Relative Source Binding doesn't work in this case. It actually works from a data template, you can find many examples of this on the Internets. But here (you were right, David, in your comment) ToolTip is a special beast that is not placed correctly in the VisualTree (it's a property, not a control per se) and it doesn't have access to the proper name scope to use relative binding.

After some more searching I found this article, which describes this effect in details and proposes an implementation of a BindableToolTip.

It might be an overkill, because you have other options -- like using a static property on a class (as in Dabblernl's response) or adding a new instance property to your Item.

First attempt :)

You should consult with the Relative Source Binding types (in this cheat sheet for example):

So your binding will look somehow similar to this:

{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ItemsControl}}, Path= GlobalText}