Your direct invocation of the "get_Controls" method gets me going again.
I'm glad that works, but reflecting on this it seems that one pretty much *have* to offer the return-type to PROPERTY/GetProperty when there are ambiguities of this sort, which there will be. That's a bit iffy syntactically, even though the implementation is easy enough. And of course the error-message would still be pretty confusing. C#'s type inference mechanism tells me that in the example, if foo has type TestPropertiesB, then bar in var bar = foo.MyProperty(); has type String, this being an error: var bar = (int) foo.MyProperty(); whereas in var bar = ((TestPropertiesA) foo).MyProperty(); bar is an int. I guess one could write a custom Binder that would implement a 'most specific property' thing, but that does kind of feel like overkill. Regards, Iver