Wpf 合并XPS文档以进行打印

我有一个wpf应用程序处理打印功能，用于将多个xps文档合并为单个xps文档。工作时，它会触发错误“无法在仅写模式下执行读取操作”

我已从memorystream加载数据

xpsDoc = new XpsDocument(pack, CompressionOption.SuperFast, inMemPackageName);

我使用了合并引用

FixedDocumentSequence sourceSequence = doc.GetFixedDocumentSequence();



foreach (DocumentReference dr in sourceSequence.References)                                             
{

    DocumentReference newDocumentReference = new DocumentReference();
    newDocumentReference.Source = dr.Source;
    (newDocumentReference as IUriContext).BaseUri = (dr as IUriContext).BaseUri;
    FixedDocument fd = newDocumentReference.GetDocument(true);
    newDocumentReference.SetDocument(fd);                                                seqNew.References.Add(newDocumentReference);
}

然后我用这个代码来打印

XpsDocumentWriterwriter=PrintQueue.CreateXpsDocumentWriter(printQueue);                  
DocumentPaginator paginator = seqNew.DocumentPaginator;
if (paginator.PageCount == MassPrintings.Count())
{
   writer.Write(seqNew);
}

---

请给我建议一个解决方案

您能提供导致错误的代码吗？使用xpsdocument writer时，它会触发错误XpsDocumentWriter=PrintQueue.CreateXpsDocumentWriter（PrintQueue）@鲍勃，你能为这个问题提出解决办法吗？。。。