public IActionResult SaveEntity(ChapterViewModel chapterViewModel) { if (!ModelState.IsValid) { IEnumerable <ModelError> allErrors = ModelState.Values.SelectMany(v => v.Errors); return(new BadRequestObjectResult(allErrors)); } if (chapterViewModel.Id == 0) { _chapterService.Add(chapterViewModel); } else { _chapterService.Update(chapterViewModel); } _chapterService.SaveChanges(); return(new OkObjectResult(chapterViewModel)); }