public static void SortDicWithLinq(){
            Dictionary<DateTime, String> dd = new Dictionary<DateTime, String>();
            DateTime dt = DateTime.Now;
            dd.Add(dt, "bbb");
            dd.Add(dt.AddDays(-1),"ccc");
            dd.Add(dt.AddDays(1), "aaa");

            Console.WriteLine("Org===============");
            travelDicKeyDate(dd);

            Dictionary<DateTime, String> dicAsc = dd.OrderBy(p => p.Key).ToDictionary(p => p.Key, p => p.Value);
            Console.WriteLine("Asc===============");
            travelDicKeyDate(dicAsc);

            Dictionary<DateTime, String> dicDesc = dd.OrderByDescending(p => p.Key).ToDictionary(p => p.Key, p => p.Value);
            Console.WriteLine("Desc===============");
            travelDicKeyDate(dicDesc);
        }        public static void travelDicKeyDate(Dictionary<DateTime, String> dic)
        {
            foreach (KeyValuePair<DateTime,String> kvp in dic)
            {
                Console.WriteLine(String.Format("{0}  {1}",kvp.Key,kvp.Value));
            }
        }