WCF provides a message-oriented programming framework. We use WCF to transmit messages between applications. Internally WCF represents all the messages by a Message class. When WCF transmits a message it takes a logical message object and encodes it into a sequence of bytes. After that WCF reads those bytes and decodes them in a logical object. The process forms a sequence of bytes into a logical object; this is called an encoding process. At runtime when WCF receives the logical message, it transforms them back into corresponding .Net objects. This process is called serialization.
WCF supports three basic serializers:
- XMLSerializer
- NetDataContractSerializer
- DataContractSerializer
WCF deserializes WCF messages into .Net objects and serializes .Net objects into WCF messages. WCF provides DataContractSerializer by default with a servicecontract. We can change this default serializer to a custom serializer like XMLSerializer.
- [XmlSerializerFormat]
- [ServiceContract]
- public interface IService1
- {
- [OperationContract]
- void AddAuthor(Author author);
- }
The XmlSerializerFormat attribute above the ServiceContract means this serializer is for all operation contracts. You can also set a separate contract for each operation.
XMLSerializer
We can find XMLSerializer in the System.Xml.Serialization namespace. WCF supports this serialization from .Net 1.0. It is used by default with the ASP.Net webservices (ASMX).
NetDataContractSerializer
NetDataContractSerializer is analogous to .Net Remoting Formatters. It implements IFormatter and it is compatible with [Serializable] types. It is not recommended for service oriented design.
DataContractSerializer
DataContractSerializer is a default serializer for WCF. We need not to mention DataContractSerializer attribute above the service contract.
