Default values of inherited fields not shown in UI Builder

[uDamian]

UI Builder did not yet learn how to allow users to customize the use of their custom C# elements inside the Builder. We are working towards first having a functionally complete Builder first before we expose extensibility features.

For this specific question, what I’d do is set a default value for your text in the ButtonTranslatable’s constructor. If no attribute is given in UXML, the default value will win. If an attribute is given in UXML, the UXML value will win.

You can also extend the list of attributes shown in the Builder’s inspector for your custom attribute by exposing a C# property. See this post for more details:

UI builder and custom elements

Yep, you can do that by inheriting from VisualElement. You can then define a UxmlFactory inside your element class to expose it to UXML (so you can create it with a tag with same name as you C# type). And you can define a UxmlTraits class to add custom attributes that you can then set in UXML. These custom attributes will then be exposed in the UI Builder inspector, like Text, Binding Path, Name, etc. (in your screenshot). Here’s a full example of a custom element and some UXML attribute declara…