I have client side 2 adapter-based Entities. CustomerX and CustomerY.

They are not related and come from different sources.

They both have a customerID field. I'd like to know all the CustomerXs that intersect with CustomerY on the cutomerID field.

Is there a client side way using Linq.Intersect perhaps?

Ian

Once they are in memory you are certainly allowed to use any and alll extension methods on IEnumerable. I would just try to join them in memory using linq.

Indeed InMemory linq query could be used in this case. You can do that using a join or simply an intersect:

var results = from c in customersX.Intersect(customersY)                        
              select c;