Use the DataContractSerializer class to serialize and deserialize instances of a type into an XML stream or document. For example, you can create a type named Person with properties that contain essential data, such as a name and address. You can then create and manipulate an instance of the Person class and write all of its property values in an XML document for later retrieval, or in an XML stream for immediate transport. Most important, the DataContractSerializer is used to serialize and deserialize data sent in Windows Communication Foundation (WCF) messages. Apply the DataContractAttribute attribute to classes, and the DataMemberAttribute attribute to class members to specify properties and fields that are serialized.