c# - 尝试使用 PdfStamper 和 MemoryStream 将数据添加到现有 PDF 然后通过电子邮件发送

Question

这是我的代码块。它编译得很好，当我触发事件时，我收到了电子邮件，但是我在打开时收到此错误电子邮件附件错误（Acrobat 无法打开“Att00002.pdf”，因为它不是受支持的文件类型，或者因为文件已损坏（例如，它作为电子邮件附件发送并且未正确解码。）

string agentName = "My Name";            
MemoryStream _output = new MemoryStream();
            PdfReader reader = new PdfReader("/pdf/Agent/Specialist_Certificate.pdf");
            using (PdfStamper stamper = new PdfStamper(reader, _output))
            {
                AcroFields fields = stamper.AcroFields;
            // set form fields
            fields.SetField("FIELD_AGENT_NAME", agentName);
            fields.SetField("FIELD_DATE", AvalonDate);

            // flatten form fields and close document
            stamper.FormFlattening = true;
            SendEmail(_output);
            DownloadAsPDF(_output);
            stamper.Close();
        }

private void SendEmail(MemoryStream ms)
{
    Attachment attach = new Attachment(ms, new System.Net.Mime.ContentType("application/pdf"));
    EmailHelper.SendEMail("myemail@myemail.com", "mjones@globusfamily.com", null, "", "Avalon Cert", "Hope this works", EmailHelper.EmailFormat.Html,attach);
}

已编辑 *************************************

        using (MemoryStream _output = new MemoryStream())
        {
            using (PdfStamper stamper = new PdfStamper(reader, _output))
            {
                AcroFields fields = stamper.AcroFields;
                // set form fields
                fields.SetField("FIELD_AGENT_NAME", agentName);
                fields.SetField("FIELD_DATE", AvalonDate);

                // flatten form fields and close document
                stamper.FormFlattening = true;
            }
            SendEmail(_output);
        }

Answer 1

你在stamper.close()里面打电话using (PdfStamper stamper = new PdfStamper(reader, _output))。除了手动关闭（）之外，它using会在退出时自动关闭压模，因此从技术上讲，压模试图关闭两次。正因为如此，它也试图MemoryStream不止一次地关闭。这就是异常的来源。

我会为您MemoryStream和PdfStamper（修改并取自：Getting PdfStamper to work with MemoryStreams (c#, itextsharp)）使用答案中的技术：

using (MemoryStream _output = new MemoryStream()) {
  using (PdfStamper stamper = new PdfStamper(reader, _output)) {
// do stuff      
  }    
}