GetCSV

 public static string GetCSV<T>(this IEnumerable<T> list) where T : IConvertible
        {
            return string.Join(",", list.Select(x => x.ToString()).ToArray());
        }

        public static List<T> GetListFromCSV<T>(this string csv) where T : IConvertible
        {
            if (string.IsNullOrEmpty(csv)) return new List<T>();
            return csv.Split(',').Select(x => (T)Convert.ChangeType(x, typeof(T))).ToList();
        }