private void btnBookAdd_Click(object sender, RoutedEventArgs e) { if (String.IsNullOrWhiteSpace(txtISBN.Text) || String.IsNullOrWhiteSpace(txtBookTitle.Text) || String.IsNullOrWhiteSpace(txtBookAuthor.Text) || String.IsNullOrWhiteSpace(txtPublisher.Text) || String.IsNullOrWhiteSpace(txtYearOfPublication.Text) || String.IsNullOrWhiteSpace(txtURIL.Text) || String.IsNullOrWhiteSpace(txtURIM.Text) || String.IsNullOrWhiteSpace(txtURIS.Text)) { MessageBox.Show("Information cannot be empty!", "Error", MessageBoxButton.OK, MessageBoxImage.Error); } else { int year = 0; Int32.TryParse(txtYearOfPublication.Text, out year); Book book = new Book() { ISBN = txtISBN.Text, BookTitle = txtBookTitle.Text, BookAuthor = txtBookAuthor.Text, Publisher = txtPublisher.Text, YearOfPublication = year, ImageURI_L = txtURIL.Text, ImageURI_M = txtURIM.Text, ImageURI_S = txtURIS.Text }; var addBookResponse = SqlHandler.AddBook(book); if (addBookResponse.Success) { MessageBox.Show("Successfully added " + book.BookTitle + ".", "Success", MessageBoxButton.OK, MessageBoxImage.Information); lbxBook.Items.Add(book); } else { MessageBox.Show("Error adding " + book.BookTitle + ".\n\n" + addBookResponse.ErrorText, "Error", MessageBoxButton.OK, MessageBoxImage.Error); } } }