A patent filing should describe an invention in detail and, if granted or otherwise published by a patent office, will become publicly available.
A trade secret, in contrast, generally comprises information that derives economic value from being kept secret and that is subject to reasonable efforts to maintain its secrecy. Creation of a trade secret does not involve any official filing and the economic value of the trade secret can be vitiated via disclosure of the trade secret information.
Accordingly, since patent filings are typically published, trade secret and patent protection generally cannot be concurrently used to protect a feature of an invention that is disclosed in a published patent filing.