Unresolved Binding / Assertion Failure When Using UI Toolkit Localization Binding

Hi,
I’m seeing persistent “unresolved binding” and AssertionException: Assertion failure. Value was False Expected: True errors whenever I try to bind a UI Toolkit <Label> to a localized string in my UXML.
Im on Unity 6.34f1
com.unity.localization 1.5.4
Using the built-in Editor & UI Builder.

Steps:

  • Created a UIDocument in my Scene, referencing a .uxml that has a <Label> with some “LocalizedString” property bound.
  • The UI Builder inserted <Bindings>... lines in the .uxml.
  • As soon as I do that, I start getting “Unresolved binding” in the Inspector and console spam of Assertion failure. Value was False.
  • If I remove the data binding lines from the .uxml, the errors go away.

So I can avoid the bug by removing all <Bindings> blocks from my UXML and localizing purely via C#. But of course, it means I can’t rely on the built-in data-binding approach from UI Builder. Is this the way to go?

Is this a known issue with UI Toolkit data-binding to the Localization package?
Any official fix?

Thanks

Hi,
Could you please file a bug report so we can investigate? Unity QA: Building quality with passion