public OperationResult <BookInfoDto> AddBooking(BookRequestDto bookRequestDto) //operation result . if data is null then not avaible. book oluşturulduğunda ekrana info sayfasını vercek { if (CarRepository.IsAvaible(bookRequestDto.carId, bookRequestDto.RentStartDate, bookRequestDto.RentEndDate)) { var book = CreateBooking(bookRequestDto); BookRepository.AddAndSave(book); return(new OperationResult <BookInfoDto>(true, "Successfully booked", (int)HttpStatusCode.OK, book.ToBookInfoDto())); } else { return(new OperationResult <BookInfoDto>(false, "These dates are not available for the selected car", (int)HttpStatusCode.NotFound, null)); } }