public IHttpActionResult Attach(List <int> list, [FromUri] int city_id) { if (!_cityService.Exist(city_id)) { return(BadRequest("ERROR_CITY_NOT_EXISTS")); } if (list == null || list.Count == 0) { return(BadRequest("ERROR_EMPTY_LIST")); } var result = _cityService.Attach(list, city_id); return(Ok(result)); }