private void CreateEdit(object sender, EventArgs e) { if (!CheckInputFields()) { return; } if (_loanToEdit == null) { var newLoan = new Loan { StudentId = ((Student)studentsListBox.SelectedItem).Id, BookId = ((Book)booksListBox.SelectedItem).Id, PickupDate = DateTime.Now, ReturnDeadline = DateTime.Now.AddDays(21) }; _loansRepository.Add(newLoan); } else { _loanToEdit.StudentId = ((Student)studentsListBox.SelectedItem).Id; _loanToEdit.BookId = ((Book)booksListBox.SelectedItem).Id; _loansRepository.Edit(_loanToEdit); } Close(); }