I was trying to develop sample application accessing SharePoint lists using
ADO.NET Data Services.
BUT NOTHING WORKED :s
When I try to access listdata.svc from the browser i got this exception
“Could not load type 'System.Data.Services.Providers.IDataServiceUpdateProvider' from assembly System.Data.Services”
And When i try to reference the same service from Visual studio 2010 in a Windows application i got 401 unauthorized and 400 bad request.
after a lot of research you need to make sure that ADO.NET Data Services CTP v1.5 CTP installed, also if your operating system is Windows Server 2008 R2 make sure to install this fix
ADO.NET Data Services Update for .NET Framework 3.5 SP1 for Windows 7 and Windows Server 2008 R2
everything will work after that, you can access your site
Try to access the list data service
you will xml with existing lists in you site
You can also access the list data through appending the list name to the service url