Validator problem - file not attached

[user_looser]

Hi all, can anyone help me with setting validator, so that it allowed me to send form without attached file?

This is corresponding rule in SourcesTable.php:

This is my add action (click to enlarge image):

Thank you very much!

[KevinPfeifer]

1. Input files are not scalar, so remove the ->scalar()
2. maxLength on a input field also doesn’t make sense, remove that
3. allowEmptyString() is also not what you want here. You want

$validator->allowEmptyFile('last_stability_exam_folder');

[user_looser]

Thank you very much.