public IEnumerable GetErrors(string propertyName) {
switch (propertyName) {
case nameof(Value):
return string.IsNullOrWhiteSpace(Value) ? new[] { AppStrings.Common_RequiredValue } :
IsValueAcceptable ? null : new[] { _previousInacceptanceReason ?? AppStrings.AcRoot_FolderIsUnacceptable };
default:
return null;
}
}