Code to find the duplicate record in C#

 var UserList = new ArrayList { "Amatya", "Aditya", "Amatya", "Sanjay", "Ram", "Sanjay", "Mahadev" };
            var RepeatVal =
                (from string item in UserList select item).GroupBy(s => s).Select(
                    group => new { Word = group.Key, Count = group.Count() }).Where(x => x.Count >= 2);

            foreach (var result in RepeatVal)
            {
                ddlList.Items.Add(result.Word);
				}