RIA Services versus WCF Services

Question

I'm rewriting an LOB application whose architecture is like this:

Silverlight && Windows Mobile -> WCF -> Entity Framework -> Database.

The mobile app was supposed to be able to do certain things as the silverlight app. What benefits would I get from using RIA Services here? Whats the advantage and disadvantage of RIA Services over WCF?

Solution 1

.NET RIA Services was created for Silverlight that runs in the browser. Silverlight is running a special version of the the .NET framework and in an N-tier application Silverlight is unable to share assemblies with the server side. By employing some clever code generation .NET RIA Services makes this gap almost invisible to the developer. Classes similar to the domain classes are code generated on the client side, and ways to move objects back and forth between client and server are also made available.

You will probably be able to call into a .NET RIA Service from Windows Mobile, but I don't think it will particular easy and currently you may in fact have to reverse engineer what's sent on the wire (JSON is used). WCF on the other has a much more broad scope, but doesn't support Silverlight development in the same way that .NET RIA Services does.

If you are writing a Silverlight only N-tier application .NET RIA Services are very powerful. If however Silverlight is only one of several clients WCF is probably a better choice.

Please note the .NET RIA Services hasn't been released yet, but a preview is available for download.

Solution 2

WCF RIA Services introduces several solutions for challenges you run into when using WCF from Silverlight. For instance, asynchronous loading of queries using the EntityQuery<T> is much easier than the Begin..End solution offered by WCF. Also, RIA provides integrated change tracking from your client that allow to submit or reject multiple changes as one change set. RIA will bundle all these changes into one request, but from your Domain Service it behaves as it were individual calls. As a long time WCF developer I can tell you that that is a breeze.

Solution 3

Ria services are created just to be used with Silverlight. They are substantially a standard "package" ready to be used by Silverlight. The advantage is that you have a lot of services without need to write code i.e.:

1. Support for data annotations
2. Support for membership provider and login
3. Support for transferring to silverlight server side generated exceptions. There is a difficulty in silverlight that make difficultthe normal error transfer of exception through FaultContract. The point is that the browser is not able to handle all error codes. Ria services solve this with a trick

All things done by Ria can be done with WCF and with other available software and in particular with Wcf data services. For instance for data annotations I found this library that do a better job than Ria services, support for membership just require activating the already existing membership endpoint of a WCF service, and finally the exception problem is easily resolved by writing a WCF behaviour. Code is available here:http://www.silverlightshow.net/Storage/10Tips.zip The point is that with Ria Service you have all this in a mouse click!. On the other side Ria Services are really difficult to customize...so if you don't like the standard solution they offer you simply can't use them