Is this the correct use of WCF and data contracts?

Question

I'm still pretty new to Silverlight, quite new to WCF, and am trying to broaden my horizons into both. I'd like to learn what is considered to be good practices while doing so.

On the client side, I have a Silverlight application. On the server side, I have a database that the Silverlight application will be utilizing. In between the two (okay, it's server-side, but...), I have a WCF service that the client calls upon to get the data from the database.

I have created a class that is marked as a DataContract and is used by the WCF service. That class is an object model populated with data from the database. On the client side, when it requests and receives an instance of this class, it uses the instance data to instantiate and populate a client-defined object that has additional client-defined members.

It's my use of the DataContract that most worries me. To create an instance of an object to be serialized and sent, only to be pillaged for its data so another object can be created seems...inefficient. But if it's considered a good practice I can get past that.

I did consider going the route of a web handler (.ashx) and using a proprietary binary standard to communicate the data, but I think going the WCF route may be more applicable and usable in the future (thinking: job).

Answer 1

I don't see any particular problem with your approach.

In my mind what you're describing is the transfer of data from service to client as a DTO (data-transfer object), and then using that DTO to populate a view model object. It is also quite common for the DTO and view model objects to use varying levels of granularity in terms of the data they represent (typically DTOs will be more coarse grained), and the view model will contain behaviour that is specific to the UI.

You might want to look at tools and frameworks that help in the mapping between DTOs and view model objects. One of my favourites is AutoMapper.