public IActionResult AddNewEvent([FromBody] NewEvent newEvent) { if (!ModelState.IsValid) { string errorMessage; if (ModelState.Values.Select(x => x.Errors.Count > 0).ToList().Count > 1) { errorMessage = "UzupeĊnij poprawnie formularz."; } else { errorMessage = ModelState.Values.FirstOrDefault().Errors.FirstOrDefault().ErrorMessage; } return(BadRequest(errorMessage)); } return(Ok(eventsService.AddNewEvent(newEvent))); }