Message contract translation to SOAP message

Question

How .NET framework creates SOAP message from message contract? Which serializer class is used to serialize the message contract?

Answer 1

Deep below the cover, the SOAP message is mainly constructed using SerializeReply method of class implementing System.ServiceModel.Dispatcher.IDispatchMessageFormatter interface. There are two internal formatters using XmlObjectSerializer and XmlSerializer implementations to serialize message headers and body.

Luckily, there is another, public class that provides wanted functionality. The TypedMessageConverter internally creates dispatch message formatter in similar fashion to formatter set for a dispatch operation. It uses private GetOperationFormatter method in Create static method overloads in order to create instance of internal System.ServiceModel.Description.XmlMessageConverter class.

After creating the TypedMessageConverter implementation instance, one can pass message contract instance into ToMessage method. Finally, call to ToString method on Message instance returns expected SOAP message string.

TypedMessageConverter converter = TypedMessageConverter.Create(
    typeof( CustomMessage ),
    "http://schemas.cyclone.com/2011/03/services/Service/GetData",
    "http://schemas.cyclone.com/2011/03/data",
    new DataContractFormatAttribute() { Style = OperationFormatStyle.Rpc } );
CustomMessage body = new CustomMessage()
{
    // Setting of properties omitted
};
Message message = converter.ToMessage( body, MessageVersion.Soap12 );
string soapMessage = message.ToString();

Answer 2

This will depend on your configuration. By default basicHttpBinding and wsHttpBinding use the DataContractSerializer class. As far as the SOAP envelopes are concerned I don't know what classes are used and I am not sure if they would be public (I might be wrong on this).