Dreaded NotFound and Object reference not set to an instance of object exceptions in WCF RIA Services

Recently while developing an WCF RIA Services and SL4 client, I was facing these dreaded "NotFound" and "Object reference not set to an instance of object". After a bit of googling figured out the problem and its root cause.

NotFound exception

To view the actual error, you will have to use Fiddler. In the Fiddler, you can find out the actual error as "HTTP 404, Page Not Found error". This is because, WCF RIA service sits in the same virtual directory of you SL4 application. But the necessary config entries were not getting copied to the SL4 application config file.

For instance, When you create an RIA service and SL4 client; you will get the following projects in your solution;

xxxRIASerices.Host

xxxRIAServices.Host.Web

xxxSLRIAClient

xxxSLRIAClient.Web

The necessary config entries for enabling RIA service will be available in the App.Config file in xxxRIAServices.Host.Web (Basically the connectionStrings, System.Web, System.webServer sections). Copy those sections to xxxSLRIAClient.Web Web.Config file.

Bingo, we have get rid of the NotFound exception.

Object reference not set to an instance of object exception

I am sure, you will be getting this error. :) To solve this error, copy paste the System.ServiceModel section from xxxRIAServices.Host.Web App.Config to xxxSLRIAClient.Web Web.Config file.

Yes, now you should have get rid of these 2 exceptions and your WCF RIA service and SL client App will be working like charm.