C#月份和日期转大写和C#集合分组

     //日转化为大写
        private static string DaytoUpper(int day, string type)
        {
            if (day < 20)
            {
                return MonthtoUpper(day, "") + type;
            }
            else
            {
                String str = day.ToString();
                if (str[1] == '0')
                {
                    return NumtoUpper(Convert.ToInt16(str[0].ToString())) + "十" + type;
                }
                else
                {
                    return NumtoUpper(Convert.ToInt16(str[0].ToString())) + "十"
                        + NumtoUpper(Convert.ToInt16(str[1].ToString())) + type;
                }
            }
        }
        //月转化为大写
        private static string MonthtoUpper(int month, string type)
        {
            if (month < 10)
            {
                return NumtoUpper(month) + type;
            }
            else
                if (month == 10) { return "十" + type; }

            else
            {
                return "十" + NumtoUpper(month - 10) + type;
            }
        }
        private static string NumtoUpper(int num)
        {
            String str = num.ToString();
            string rstr = "";
            int n;
            for (int i = 0; i < str.Length; i++)
            {
                n = Convert.ToInt16(str[i].ToString());//char转数字,转换为字符串，再转数字
                switch (n)
                {
                    case 0: rstr = rstr + "〇"; break;
                    case 1: rstr = rstr + "一"; break;
                    case 2: rstr = rstr + "二"; break;
                    case 3: rstr = rstr + "三"; break;
                    case 4: rstr = rstr + "四"; break;
                    case 5: rstr = rstr + "五"; break;
                    case 6: rstr = rstr + "六"; break;
                    case 7: rstr = rstr + "七"; break;
                    case 8: rstr = rstr + "八"; break;
                    default: rstr = rstr + "九"; break;
                }

            }
            return rstr;
        }

　　C#集合分组：

  var _lstMonthGroup = _logInfoList.GroupBy(x => x.month);
            string _strJson = string.Empty;
            _strJson += "[";
            foreach (IGrouping _monthData in _lstMonthGroup)
            {
                _strJson += "{ ";
                _strJson += "\"moth\":\"" + _monthData.Key + "\",";
                _strJson += "\"mothData\":[";
                //按天分组
                var _lstDayGroup = _monthData.GroupBy(c => c.monthAndday).ToList();
                foreach (var _dayData in _lstDayGroup)
                {
                    _strJson += "{";
                    _strJson += "\"dayName\":\"" + _dayData.Key + "\",";
                    _strJson += "\"dayDta\":[";
                    foreach (var vv in _dayData)
                    {
                        _strJson += "{";
                        _strJson += "\"detial\":\"" + vv.detial + "\"";
                        _strJson += "},";
                    }
                    _strJson = _strJson.TrimEnd(',');
                    _strJson += "]";
                    _strJson += "},";
                }
                _strJson = _strJson.TrimEnd(',');
                _strJson += "]";
                _strJson += "},";
            }
            _strJson = _strJson.TrimEnd(',');
            _strJson += "]";