validateValue method
Implementation
List<String> validateValue(T? value) {
List<String> errors = [];
if (isRequired == true && _isValueEmpty(value)) {
errors.add('$label is required');
return errors;
}
if (_isValueEmpty(value)) return errors;
if (rules != null) {
final newErrors = rules!.map((rule) => rule(value)).where((error) => error != null && error.isNotEmpty).cast<String>().toList();
errors.addAll(newErrors);
}
return errors;
}