Data and Member contract in wcf service

Since a lot of programmers were overwhelmed with the [DataContract] and [DataMember] attributes, with .NET 3.5 SP1, Microsoft made the data contract serializer handle all classes - even without any of those attributes - much like the old XML serializer.

So as of .NET 3.5 SP1, you don't have to add data contract or data member attributes anymore - if you don't then the data contract serializer will serialize all public properties on your class, just like the XML serializer would.

HOWEVER: by not adding those attributes, you lose a lot of useful capabilities:

without [DataContract], you cannot define an XML namespace for your data to live in
without [DataMember], you cannot serialize non-public properties or fields
without [DataMember], you cannot define an order of serialization (Order=) and the DCS will serialize all properties alphabetically
without [DataMember], you cannot define a different name for your property (Name=)
without [DataMember], you cannot define things like IsRequired= or other useful attributes
without [DataMember], you cannot leave out certain public properties - all public properties will be serialized by the DCS.

So for a "quick'n'dirty" solution, leaving away the [DataContract] and [DataMember] attributes will work - but it's still a good idea to have them on your data classes - just to be more explicit about what you're doing, and to give yourself access to all those additional features that you don't get without them.
[from here][^]

You can find more details about contracts here:
http://www.dotnet-tricks.com/Tutorial/wcf/3ISW280913-Understanding-different-types-of-WCF-Contracts.html[^]
Understanding Contracts in WCF[^]

-KR