private void addBtn_Click(object sender, RoutedEventArgs e) { try { string isbn = isbnTextBox.Text; string author = authorTextBox.Text; string title = titleTextBox.Text; string publisher = publisherTextBox.Text; int publishedAt = int.Parse(publishedAtTextBox.Text); int pagesCount = int.Parse(pagesCountTextBox.Text); string price = priceTextBox.Text; Book book = new Book(isbn, author, title, publisher, publishedAt, pagesCount, price); foreach (Book otherBook in bookList.Books) { if (book.ISBN == otherBook.ISBN) { if (book.Equals(otherBook)) { break; } else { throw new FormatException("ISBN must be unique for different editions."); } } } bookList.AddBook(book); } catch (OverflowException ex) { MessageBox.Show(ex.Message); } catch (ArgumentException ex) { MessageBox.Show(ex.ParamName); } catch (FormatException ex) { MessageBox.Show(ex.Message); } catch { MessageBox.Show("Wrong data"); } return; }