I'm trying to create an OData WCF service using NHibernate and I'd like to use $expand in queries. I found an interface IExpandProvider, which I guess, is (was) exactly for this purpose. But it says The IExpandProvider interface is deprecated. What's the current way to implement expand?
Starting with V2 the IExpandProvider is deprecated because it can't support the new query options, like $select. The "new" way is to implement IQueryable. All the query options are translated into LINQ expression trees. If you want a bit more detail on how that is done see this series: http://blogs.msdn.com/b/vitek/archive/2010/02/25/data-services-expressions-part-1-intro.aspx. The part talking about $expand is here: http://blogs.msdn.com/b/vitek/archive/2010/07/15/data-services-expressions-part-9-expansions.aspx