Documentation Errors

Unity Engine
1

The manual docs about defining attributes on custom subclasses of VisualElement contains errors that make it hard to get started. They include this example:

class StatusBar : VisualElement
{
    public new class Factory : UxmlFactory<StatusBar, UxmlTraits> {}

    public new class Traits : base.UxmlTraits
    {
        UxmlStringAttributeDescription m_Status = new UxmlStringAttributeDescription { name = "status" };

        public override IEnumerable<UxmlChildElementDescription> uxmlChildElementsDescription
        {
            get { yield break; }
        }

        public override void Init(VisualElement ve, IUxmlAttributes bag, CreationContext cc)
        {
            base.Init(ve, bag, cc);
            ((StatusBar)ve).status = m_Status.GetValueFromBag(bag, cc);
        }
    }

    // ...
}

Line 3 should refer to Traits instead of UxmlTraits:

public new class Factory : UxmlFactory<StatusBar, UxmlTraits> {} // <-- WRONG

public new class Factory : UxmlFactory<StatusBar, Traits> {} // <-- RIGHT

… so that the newly declared inner Traits class is actually used.

It also uses tries to refer to the base class as “base.UxmlTraits” for some reason, which is a compiler error. Removing “.base” fixes that.

2

Hey! Thx for the report.

I can confirm that this sample is fixed in the latest docs:

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