private void RefreshBookInfoListBox() { BookInfoListBox.Items.Clear(); var selected = BooksListBox.SelectedItem.ToString(); var checkedBook = _bookRepository.GetAllBooks() .FirstOrDefault(book => book.ToString() == selected); if (checkedBook == null) { return; } BookInfoListBox.Items.Add($"{checkedBook.PageCount} pages"); BookInfoListBox.Items.Add($"Genre: {checkedBook.Genre}"); var bookCopies = _bookCopyRepository.GetBookCopiesByBook(selected); BookInfoListBox.Items.Add($"Number of copies: {bookCopies.Count}"); BookInfoListBox.Items.Add( bookCopies.All(bookCopy => bookCopy.Status != BookStatus.ReadOnly) ? $"Available copies: {bookCopies.Count(bookCopy => bookCopy.Status == BookStatus.Available)}" : "Read only"); }