Post_16_25.cs

[HttpPost]
[ExportModelStateToTempData]
public IActionResult AddOrEdit(AddOrEdit addOrEdit)
{
  if (!this.ModelState.IsValid)
    return this.RedirectToAction("AddOrEdit");

  Data.Entities.Book book = addOrEdit.Id == null ? new Data.Entities.Book() : this.bookRepository.GetById((int)addOrEdit.Id);

  this.CreateOrUpdateLocalizationsFor(book);
  book.Year = addOrEdit.Year;

  if (addOrEdit.Id == null)
    this.bookRepository.Create(book);

  else this.bookRepository.Update(book);

  this.storage.SaveChanges();
  return this.RedirectToAction("Index");
}