ExpressionEqualityComparer.

Wherever an IEqualityComperer is used, pass EqualityComparer.Create((t1, t2) => t1.AmIEqualTo(t2))

where AmIEqualTo is your custom equality method.

e.g. List myList = ... ; var myDistinctObjects = myList.Distinct(EqualityComparer.Create((t1,t2) => t1.AmIEqualTo(t2)));

or

EqualityComparer.Create(t => t.GetTVal()); where GetTVal() is a function that returns a TVal that represents the equivalence of the T objects.