Wrap a delegate in an IEqualityComparer

Question

Several Linq.Enumerable functions take an IEqualityComparer<T>. Is there a convenient wrapper class that adapts a delegate(T,T)=>bool to implement IEqualityComparer<T>? It's easy enough to write one (if your ignore problems with defining a correct hashcode), but I'd like to know if there is an out-of-the-box solution.

Specifically, I want to do set operations on Dictionarys, using only the Keys to define membership (while retaining the values according to different rules).

Answer 1

I'm going to answer my own question. To treat Dictionaries as sets, the simplest method seems to be to apply set operations to dict.Keys, then convert back to Dictionaries with Enumerable.ToDictionary(...).