字典根據key 或者值排序

   List<KeyValuePair<int, float>> list = new List<KeyValuePair<int, float>>(_dic_new);
        list.Sort(delegate (KeyValuePair<int, float> s1, KeyValuePair<int, float> s2)
        {
            //從大到小
            return s2.Key.CompareTo(s1.Key);
            //從小到大
            //return s1.Value.CompareTo(s2.Value);
        });