autovalidateMode property
Used to enable/disable this checkbox auto validation and update its error text.
Defaults to AutovalidateMode.onUnfocus.
If AutovalidateMode.onUserInteraction, this checkbox will only auto-validate after its content changes. If AutovalidateMode.always, it will auto-validate even without user interaction. If AutovalidateMode.disabled, auto-validation will be disabled.
Implementation
final AutovalidateMode autovalidateMode;