// Process the SOAP message received and write to log file.
public override void ProcessMessage(SoapMessage message) 
{
   switch (message.Stage) 
   {
      case SoapMessageStage.BeforeSerialize:
         WriteOutputBeforeSerialize(message);
         break;
      case SoapMessageStage.AfterSerialize:
         WriteOutputAfterSerialize(message);
         break;
      case SoapMessageStage.BeforeDeserialize:
         WriteInputBeforeDeserialize(message);
         break;
      case SoapMessageStage.AfterDeserialize:
         WriteInputAfterDeserialize(message);
         break;
      default:
         throw new Exception("invalid stage");
   }
}

// Write the contents of the outgoing SOAP message to the log file.
public void WriteOutputBeforeSerialize(SoapMessage message)
{
   FileStream myFileStream = 
      new FileStream(filename, FileMode.Append, FileAccess.Write);
   StreamWriter myStreamWriter = new StreamWriter(myFileStream);
   myStreamWriter.WriteLine("================================== Request at "
      + DateTime.Now);
   myStreamWriter.WriteLine("The method that has been invoked is: ");
   myStreamWriter.WriteLine("\t" + message.MethodInfo);
   myStreamWriter.WriteLine(
      "The contents of the SOAPAction HTTP header is:");
   myStreamWriter.WriteLine("\t" + message.Action);
   myStreamWriter.WriteLine("The contents of HTTP Content-type header is:");
   myStreamWriter.WriteLine("\t" + message.ContentType);
   if(message.OneWay)
      myStreamWriter.WriteLine(
         "The method invoked on the client shall not wait"
         + " till the server finishes");
   else
      myStreamWriter.WriteLine(
         "The method invoked on the client shall wait"
         + " till the server finishes");
   myStreamWriter.WriteLine(
      "The site where the XML Web service is available is:");
   myStreamWriter.WriteLine("\t" + message.Url);
   myStreamWriter.WriteLine("The values of the in parameters are:");
   myStreamWriter.WriteLine("Value of first in parameter: {0}",
      message.GetInParameterValue(0));
   myStreamWriter.WriteLine("Value of second in parameter: {0}",
      message.GetInParameterValue(1));
   myStreamWriter.WriteLine();
   myStreamWriter.Flush();
   myStreamWriter.Close();
   myFileStream.Close();
}

// Write the contents of the incoming SOAP message to the log file.
public void WriteInputAfterDeserialize(SoapMessage message)
{
   FileStream myFileStream = 
      new FileStream(filename, FileMode.Append, FileAccess.Write);
   StreamWriter myStreamWriter = new StreamWriter(myFileStream);
   myStreamWriter.WriteLine();
   myStreamWriter.WriteLine("The values of the out parameter are:");
   myStreamWriter.WriteLine("The value of the out parameter is: {0}",
      message.GetOutParameterValue(0));
   myStreamWriter.WriteLine("The values of the return parameter are:");
   myStreamWriter.WriteLine("The value of the return parameter is: {0}",
      message.GetReturnValue());
   myStreamWriter.Flush();
   myStreamWriter.Close();
   myFileStream.Close();
}