Programming WCF Services

Data Contract Attributes

While the Serializable attribute is workable, it is inadequate for service-oriented interaction between clients and services. It denotes all members in the type as serializable and therefore part of the data schema for that type. It is much better to have an opt-in approach, where only members the contract developer wants to explicitly include in the data contract are included. The Serializable attribute forces the data type to be serializable in order to be used as a parameter in a contract operation, and does not offer clean separation between the serviceness aspect of the type (ability to use it as a WCF operation parameter) and the ability to serialize it. The attribute offers no support for aliasing type name or members, or for mapping a new type to a predefined data contract. The attribute operates directly on member fields, and completely bypasses any logical properties used to access those fields. It would be better to allow those properties to add their values when accessing the fields. Finally, there is no direct support for versioning because any versioning information is supposedly captured by the formatters. Consequently, it is difficult to deal with versioning over time.

Yet again, the solution is to come up with new WCF service-oriented opt-in attributes. The first of these attributes is the DataContractAttribute defined in the System.Runtime.Serialization namespace:

[AttributeUsage(AttributeTargets.Enum | AttributeTargets.Struct| AttributeTargets.Class, ...