list = list.OrderByDescending(s => s).ToList();

------解决方案--------------------
tempDS = tempDS.OrderBy(od1 => od1.Value).ToList();

------解决方案--------------------
C# code

            List<string> list = new List<string>();
            list.Add("1");
            list.Add("2");
            list.Add("3");
            list.Add("4");
            list.Add("100");
            var vs = list.OrderByDescending(x=>Convert.ToInt32(x));