Learning WCF

Data Contracts

A data contract describes how CLR types map to XSD schema definitions. Data contracts are the preferred way to enable serialization of complex types included in operation signatures as parameters or return values. You create a data contract by applying theDataContractAttribute to a type. To include members in serialization, you decorate them with the DataMemberAttribute; this is an opt-in process that has nothing to do with visibility of members (public, protected, private). By default, serialization is handled by the DataContractSerializer, a new serializer for WCF that succeeds the XmlSerializer used for earlier technologies such as ASMX.

In this section, you will become acquainted with the key features of data contracts and common serialization practices, including the following:

• How to apply data contract attributes to exercise control over type serialization

• Version tolerance and data contract versioning techniques

• Implementing IExtensibleDataObject to support version tolerance

• How to work with polymorphic types in the service contract

• How enumerations, arrays, and collections are serialized

First you’ll complete a lab that illustrates many of these scenarios, and then I’ll explain the related attributes and features in greater detail.

Lab: Working with Data Contracts

For this lab you will modify a preexisting type, turning it into a data contract so that it can be included in the service contract. Using the DataContractAttribute and the DataMemberAttribute, you will ...