private void AddBookButton_Click(object sender, RoutedEventArgs e) { if (ValidateBook()) { _book = new Book(); _book.Title = BookTitleTextBox.Text.Trim(); _book.ISBN = BookIsbnTextBox.Text.Trim(); _book.ReleaseDate = PublishDatePicker.SelectedDate.Value; _book.Publisher = PublisherTextBox.Text.Trim(); _book.Pages = int.Parse(PagesTextBox.Text); _book.Genre = GenreTextBox.Text; BookDataProvider.CreateBook(_book); var newBookId = BookDataProvider.GetBookByIsbn(_book.ISBN); _bookAuthor = new BookAuthor(); _bookAuthor.BA_AuthorId = _author.AuthorId; _bookAuthor.BA_BookId = newBookId; BookAuthorDataProvider.CreateBookAuthorLink(_bookAuthor); DialogResult = true; Close(); } }