从FlowDocument创建XPS文档并即时附加它

我有一个FlowDocument，我想转换为XPS文档并将其附加到电子邮件并将它们一起发送。 我正在使用此代码

public static MemoryStream FlowDocumentToXPS(FlowDocument flowDocument, int width, int height) { MemoryStream stream = new MemoryStream(); using (Package package = Package.Open(stream, FileMode.Create, FileAccess.ReadWrite)) { using (XpsDocument xpsDoc = new XpsDocument(package, CompressionOption.Maximum)) { XpsSerializationManager rsm = new XpsSerializationManager(new XpsPackagingPolicy(xpsDoc), false); DocumentPaginator paginator = ((IDocumentPaginatorSource)flowDocument).DocumentPaginator; paginator.PageSize = new System.Windows.Size(width, height); rsm.SaveAsXaml(paginator); rsm.Commit(); } } stream.Position = 0; Console.WriteLine(stream.Length); Console.WriteLine(stream.Position); return stream; } 

然后我使用以下代码附加它：

 Attachment xps = new Attachment(FlowDocumentToXPS(FD, 768, 676), "FileName.xps", "application/vnd.ms-xpsdocument"); 

其中FD是我要转换的FlowDocument，我接收到附加的0.0KB大小的XPS文件，并且无法使用XPS Viewer打开，我在这里缺少什么？

编辑：有效的最终代码，请参阅注释

提前致谢