ToDictionary method that wraps Linq's ToDictionary, but then lists the keys and identifies duplicates for troubleshooting purposes

gistfile1.txt

    /// <summary>
    /// Provides a wrapper method around <see cref="Enumerable.ToDictionary"/> to provide details about 
    /// the duplicate keys encountered (for troubleshooting purposes).
    /// </summary>
    public static class EnumerableHelper
    {
        /// <summary>
        /// Wraps the standard LINQ ToDictionary extension method to provide additional details about
        /// the keys that were to be added to the dictionary.
        /// </summary>
        /// <typeparam name="TSource"></typeparam>
        /// <typeparam name="TKey"></typeparam>
        /// <typeparam name="TElement"></typeparam>
        /// <param name="source"></param>
        /// <param name="keySelector"></param>
        /// <param name="elementSelector"></param>
        /// <param name="equalityComparer"></param>
        /// <returns></returns>
        public static Dictionary<TKey, TElement> ToDictionaryEx<TSource, TKey, TElement>(
            this IEnumerable<TSource> source,
            Func<TSource, TKey> keySelector,
            Func<TSource, TElement> elementSelector,
            IEqualityComparer<TKey> equalityComparer)
        {
            try
            {
                return Enumerable.ToDictionary(source, keySelector, elementSelector, equalityComparer);
            }
            catch (Exception ex)
            {
                var keys =
                    (from s in source
                    select keySelector(s))
                    .OrderBy(x => x);

                var duplicatedKeys =
                    (from k in keys
                    group k by k
                    into g
                    where g.Count() > 1
                    select g.Key);

                throw new Exception(string.Format(
                    @"Duplicate key(s) encountered in ToDictionary invocation:
    {0}

All keys:
    {1}",
                    string.Join("\r\n    ", duplicatedKeys), 
                    string.Join("\r\n    ", keys)), ex);
            }
        }
    }
}