List Intersect Method Extension.

listExtension.cs

 public static class ListExtension
    {
        public static IEnumerable<TObject> Intersect<TObject>(this IEnumerable<TObject> source, IEnumerable<TObject> destination, Func<TObject, TObject, bool> predicate)
        {
            var result = new List<TObject>();
            foreach (var sourceObject in source)
            {
                foreach (var destinationObject in destination)
                {
                    if (predicate(sourceObject, destinationObject))
                        result.Add(destinationObject);
                }
            }
            return result;
        }
    }