private void Button_Click(object sender, RoutedEventArgs e)
        {
            var blockFormatterFactory = new BlockFormattersFactory();
            var pm = new PrintManager();

            var formatter = new SimpleFlowDocumentDataFormatter();
            formatter.AppendBlocks(blockFormatterFactory.Header("Simple text sample"));
            formatter.AppendBlocks(blockFormatterFactory.Text(textBox.Text));

            var doc = new SimpleDocument(formatter);
            pm.PrintPreview(doc);
        }