如何在横向(WPF，C#)中打印flowdocument？

using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Media;
using System.Windows.Xps;
using System.Windows.Xps.Packaging;

public void PrintFlowDocument(FlowDocument flowDocument)
{
    // 创建PrintDialog对象
    PrintDialog printDialog = new PrintDialog();

    if (printDialog.ShowDialog() == true)
    {
        // 将FlowDocument转换为可打印的Visual对象
        DocumentPaginator paginator = ((IDocumentPaginatorSource)flowDocument).DocumentPaginator;
        paginator.PageSize = new Size(printDialog.PrintableAreaWidth, printDialog.PrintableAreaHeight);
        Visual visual = new DrawingVisual();
        using (DrawingContext dc = ((DrawingVisual)visual).RenderOpen())
        {
            dc.DrawRectangle(Brushes.White, null, new Rect(new Point(), paginator.PageSize));
            dc.DrawRectangle(new VisualBrush(flowDocument), null, new Rect(new Point(), paginator.PageSize));
        }

        // 创建PrintDocument对象
        PrintDocument printDocument = new PrintDocument();
        printDocument.DocumentPaginator.PageSize = paginator.PageSize;
        printDocument.DocumentPaginator = paginator;

        // 实现PrintPage事件，用于绘制每一页的内容
        printDocument.PrintPage += (sender, e) =>
        {
            e.PageVisual = visual;
            e.HasMorePages = false;
        };

        // 打印FlowDocument
        printDocument.Print("FlowDocument Printing");
    }
}