Question

We’re starting to develop a new Silverlight LOB application where the DataAccess will not be based on EF, rather our own DAL code (for legacy and other not related reasons).

We are currently debating whether to use RIA Services or simple WCF Services as the Silverlight’s facade layer.

The options:

RIA Services and generated code: RIA Services will automagically create proxy classes of our Domain Model and DomainServices in our Silverlight project.
This will mean that our services will need to inherit from the DomainService class, and will require much work and workarounds to allow our custom model to be serialized normally (since we dont use EF)

WCF And shared libraries: We’ll create a DomainModel library that will be shared between both Silverlight and our server code (as offered here) giving us more control as to how our domain classes look, and how they are seen on Silverlight, and our services would remain clean as WCF doesnt require us to use any base class and give us much more power over how our services are exposed.

So the question is – given that we dont use EF, what are the pro’s to RIA Services, and what are the con’s of using WCF and shared domain?

Answer 1

I have reasonable real-life experience with both technologies.

The main pros and cons in my perspective:

RIA Services

• Pro: Development is (much) faster, even without using entity framework. You can create ViewModels, maybe mapping them with AutoMapper, and specify the attributes needed for validation / data entry / relationships. This is good practice even when using entity framework.
• Con: A lot of overhead.
• Con: Performance degrades when sending larger amounts of data (something like > 100 objects)

WCF and Shared Libraries

• Pro: Performance is relatively excellent
• Con: Development time / maintainability is not as good as RIA Services.
• Con: Cannot use databinding as well without DomainDataSource (even when using MVVM).

Update
For the data-binding part: RIA Services allows for the DomainDataSource control in Silverlight. This enables easy (async) loading with bindable properties for its state (Busy etc.) which makes it easy to do loading animations and general improvements on user experience. This can of course be done without this control, but it helps.

For the RIA services performance, I cannot seem to find the example (someone here said they lost a few months of development time rewriting domain services to conventional WCF services because of the response time that could not be met).

One more note about a Silverlight (Business Application): try zooming your browser in to 110% or 90%, some arbitrary percentage. The fonts / components will get blurred because of way the rendering works. I have confirmed this on multiple machines/configurations and have not found a fix / work around for this. Snapping to device pixels does not help here at all.

Also before you make a decision, it’s probably smart to also consider MVC3, with JQuery and HTML5 as an option for your solution. The HTML layout system might not be as good as Silverlight, but there are advantages like cross platform and mobile support.