I'm using WCF Data Services (odata) over a NHibernate backend and I have encountered problems when expanding collection properties.

I have the following (simplified) model:

public class City
{
public virtual int Id { get; set; }
public virtual string Name { get; set; }
public virtual IList<Area> Areas { get; set; }
}

public class Area
{
public virtual int id { get; set; }
public virtual string Name { get; set; }
public virtual City City { get; set; }
}

If I run the following query:

var city = (from c in session.Query<City>()
where c.ID == 1
select new ExpandedWrapper<City, IList<Area>> { Description = "Areas", ProjectedProperty0 = c.Areas, ReferenceDescription = "", ExpandedElement = c }).ToList();

I get an TargetInvocationException at ResultTransformer.TransformTuple(), line 25. TransformTuple gets called with the tuple-parameter containing a city and an area (If the City contains 5 areas, TransformTuple would get called 5 times, with the tuple containing the same city and different areas for each call).

As I understand it, the ExpandedElement will be set to city ("c") from the tuple and ProjectedProperty0 to area ("c.Areas") from the tuple, but since ProjectedProperty0 expects an IList<Area> and not an Area it throws.

I'm not sure but even if the invoke would succeed, TransformTuple would get called n times, where n is the number of associated areas...and that does not seem right either.