ResponseSoapContext.Current is null

使用WSE传输附件
可ResponseSoapContext.Current一直为NULL。不是很理解，望高人指教!



DocAttachment docInfo = _controller.GetDocInfo(sendAttId);

            Stream ms = new MemoryStream(docInfo.Content);

            SoapContext respContext =  ResponseSoapContext.Current;

            DimeAttachment dimeAttach = new DimeAttachment(

                 "image/jpg", TypeFormat.MediaType, ms);//image/jpg

            respContext.Attachments.Add(dimeAttach);

            return docInfo.Extension;

webcofig已添加

<webServices>

      <soapExtensionTypes>

        <add type="Microsoft.Web.Services2.WebServicesExtension, Microsoft.Web.Services2, Version=2.0.3.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" priority="1" group="0"/>

      </soapExtensionTypes>

    </webServices>

--------------------编程问答-------------------- 没人帮帮我吗？ --------------------编程问答-------------------- 不会,帮顶

补充：.NET技术 ,  Web Services