从4.0升级到.NET 4.6后，SOAP流未初始化

Question

升级环境以从.NET 4.6定位.NET 4.0框架后，当外部调用AuditSoap时，它会引用空requestSoapMessage对象，因为看起来似乎是ChainStream程序未初始化。

.NET 4.6处理SOAP的方式与先前版本的框架不同吗？当我逐步浏览.NET 4.0上的代码时，它按预期工作，初始化ChainStream过程（然后调用ProcessMessage）。这不会发生在.NET 4.6上 - 代码库在升级之间没有变化，因此我认为问题必须与.NET 4.6处理它的方式有关。

private static XmlDocument xmlRequest;

/// Gets the outgoing XML request
public static XmlDocument XmlRequest
{ get { return xmlRequest; } }

private static XmlDocument xmlResponse;

/// Gets the incoming XML response
public static XmlDocument XmlResponse
{ get { return xmlResponse; } }

private static SoapMessage requestSoapMessage;

/// Gets the outgoing soap message
public static SoapMessage RequestSoapMessage
{ get { return requestSoapMessage; } }

private static SoapMessage responseSoapMessage;

/// Gets the incoming soap message
public static SoapMessage ResponseSoapMessage
{ get { return responseSoapMessage; } }

/// Save the Stream representing the SOAP request
/// or SOAP response into a local memory buffer. 
public override Stream ChainStream(Stream stream)
{
    oldStream = stream;
    newStream = new MemoryStream();
    return newStream;
}

/// If the SoapMessageStage is such that the SoapRequest or
/// SoapResponse is still in the SOAP format to be sent or received,
/// save it to the xmlRequest or xmlResponse property.
public override void ProcessMessage(SoapMessage message)
{
    switch (message.Stage)
    {
        case SoapMessageStage.BeforeSerialize:
            break;
        case SoapMessageStage.AfterSerialize:                
            xmlRequest = GetSoapEnvelope(newStream);
            CopyStream(newStream, oldStream);
            requestSoapMessage = message;
            break;
        case SoapMessageStage.BeforeDeserialize:
            CopyStream(oldStream, newStream);
            xmlResponse = GetSoapEnvelope(newStream);
            responseSoapMessage = message;
            break;
        case SoapMessageStage.AfterDeserialize:
            break;
    }
}

public void AuditSoap()
{
    try
    {
        string action = System.Web.HttpContext.Current.Request.RequestContext.RouteData.GetRequiredString("action");                

        //log the Request
        logService.Audit(true,
                         LogArea.Data,
                         requestSoapMessage.MethodInfo.Name,
                         "Request",
                         action,
                         XmlRequest.InnerXml,
                         null,
                         null,
                         null,
                         XmlRequest.InnerXml);

         //log the response
         logService.Audit(true,
                         LogArea.Data,
                         responseSoapMessage.MethodInfo.Name,
                         "Response",
                         action,
                         XmlResponse.InnerXml,
                         null,
                         null,
                         null,
                         XmlResponse.InnerXml);
    }
    catch (Exception ex)
    {
        Trace.TraceError("Error in logging the web service.\n{0}", ex.ToJson());
    }
}

/// Returns the XML representation of the Soap Envelope in the supplied stream.
/// Resets the position of stream to zero.
private XmlDocument GetSoapEnvelope(Stream stream)
{
    XmlDocument xml = new XmlDocument();
    stream.Position = 0;
    StreamReader reader = new StreamReader(stream);
    xml.LoadXml(reader.ReadToEnd());
    stream.Position = 0;
    return xml;
}

/// Copies a stream.
private void CopyStream(Stream from, Stream to)
{
    TextReader reader = new StreamReader(from);
    TextWriter writer = new StreamWriter(to);
    writer.WriteLine(reader.ReadToEnd());
    writer.Flush();
}


/// Included only because it must be implemented.
public override object GetInitializer(LogicalMethodInfo methodInfo, SoapExtensionAttribute attribute)
{
    return null;
}

/// Included only because it must be implemented.
public override object GetInitializer(Type WebServiceType)
{
    return null;
}

/// Included only because it must be implemented.
public override void Initialize(object initializer)
{
}