gistfile1.txt

public class PredicateEqualityComparer<T> : EqualityComparer<T>
    {
        private readonly Func<T, T, bool> predicate;

        public PredicateEqualityComparer(Func<T, T, bool> predicate)
        {
            this.predicate = predicate;
        }

        public override bool Equals(T x, T y)
        {
            if (x != null)
            {
                return ((y != null) && predicate(x, y));
            }

            if (y != null)
            {
                return false;
            }

            return true;
        }

        public override int GetHashCode(T obj)
        {
            return 0;
        }
    }