Form Field Cascader
A pre-composed form field that wraps a Cascader control with automatic label, helper text, and error message display. Inherits from FormFieldBase for EditContext integration, generated control IDs and ARIA wiring.
Default
The wrapper supplies the trigger id and the
aria-describedby target, so the label points at the trigger and the helper text is announced with it. See Cascader for the column navigation and full-path search.Selectable Branches
By default only a leaf can be chosen, which is what you want when the value has to be a specific category.
ChangeOnSelect makes a branch a valid answer too, while its children stay navigable.Disabled and Error
ErrorText makes the field invalid and hides the helper text. A disabled field keeps the selected path visible but cannot be opened, and its hidden input is not posted.EditForm Validation
Every change calls
EditContext.NotifyFieldChanged, so validation re-runs as the user drills down. Outside an EditForm only ErrorText can make the field invalid — the control still binds normally.