C#公历转农历算法：

[C#]代码

/// <summary>      /// LunDay 的摘要说明。      /// 用法说明      /// 直接调用即可,比较简单      /// </summary>      public class LunDay      {          public LunDay()          {              //              // TODO: 在此处添加构造函数逻辑              //          }          //天干          private static string[] TianGan = { "甲", "乙", "丙", "丁", "戊", "己", "庚", "辛", "壬", "癸" };            //地支          private static string[] DiZhi = { "子", "丑", "寅", "卯", "辰", "巳", "午", "未", "申", "酉", "戌", "亥" };            //十二生肖          private static string[] ShengXiao = { "鼠", "牛", "虎", "兔", "龙", "蛇", "马", "羊", "猴", "鸡", "狗", "猪" };            //农历日期          private static string[] DayName =   {"*","初一","初二","初三","初四","初五",               "初六","初七","初八","初九","初十",               "十一","十二","十三","十四","十五",               "十六","十七","十八","十九","二十",               "廿一","廿二","廿三","廿四","廿五",                     "廿六","廿七","廿八","廿九","三十"};            //农历月份          private static string[] MonthName = { "*", "正", "二", "三", "四", "五", "六", "七", "八", "九", "十", "十一", "腊" };            //公历月计数天          private static int[] MonthAdd = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };          //农历数据          private static int[] LunarData = {2635,333387,1701,1748,267701,694,2391,133423,1175,396438              ,3402,3749,331177,1453,694,201326,2350,465197,3221,3402              ,400202,2901,1386,267611,605,2349,137515,2709,464533,1738              ,2901,330421,1242,2651,199255,1323,529706,3733,1706,398762              ,2741,1206,267438,2647,1318,204070,3477,461653,1386,2413              ,330077,1197,2637,268877,3365,531109,2900,2922,398042,2395              ,1179,267415,2635,661067,1701,1748,398772,2742,2391,330031              ,1175,1611,200010,3749,527717,1452,2742,332397,2350,3222              ,268949,3402,3493,133973,1386,464219,605,2349,334123,2709              ,2890,267946,2773,592565,1210,2651,395863,1323,2707,265877};          /// <summary>          /// 获取对应日期的农历          /// </summary>          /// <param name="dtDay">公历日期</param>          /// <returns></returns>          public string GetLunarCalendar(DateTime dtDay)          {              string sYear = dtDay.Year.ToString();              string sMonth = dtDay.Month.ToString();              string sDay = dtDay.Day.ToString();              int year;              int month;              int day;              try              {                  year = int.Parse(sYear);                  month = int.Parse(sMonth);                  day = int.Parse(sDay);              }              catch              {                  year = DateTime.Now.Year;                  month = DateTime.Now.Month;                  day = DateTime.Now.Day;              }                int nTheDate;              int nIsEnd;              int k, m, n, nBit, i;              string calendar = string.Empty;              //计算到初始时间1921年2月8日的天数：1921-2-8(正月初一)              nTheDate = (year - 1921) * 365 + (year - 1921) / 4 + day + MonthAdd[month - 1] - 38;              if ((year % 4 == 0) && (month > 2))                  nTheDate += 1;              //计算天干，地支，月，日              nIsEnd = 0;              m = 0;              k = 0;              n = 0;              while (nIsEnd != 1)              {                  if (LunarData[m] < 4095)                      k = 11;                  else                      k = 12;                  n = k;                  while (n >= 0)                  {                      //获取LunarData[m]的第n个二进制位的值                      nBit = LunarData[m];                      for (i = 1; i < n + 1; i++)                          nBit = nBit / 2;                      nBit = nBit % 2;                      if (nTheDate <= (29 + nBit))                      {                          nIsEnd = 1;                          break;                      }                      nTheDate = nTheDate - 29 - nBit;                      n = n - 1;                  }                  if (nIsEnd == 1)                      break;                  m = m + 1;              }              year = 1921 + m;              month = k - n + 1;              day = nTheDate;              //return year+"-"+month+"-"+day;                #region 格式化日期显示为三月廿四              if (k == 12)              {                  if (month == LunarData[m] / 65536 + 1)                      month = 1 - month;                  else if (month > LunarData[m] / 65536 + 1)                      month = month - 1;              }                //生肖              calendar = ShengXiao[(year - 4) % 60 % 12].ToString() + "年 ";              //天干              calendar += TianGan[(year - 4) % 60 % 10].ToString();              //地支              calendar += DiZhi[(year - 4) % 60 % 12].ToString() + " ";                //农历月              if (month < 1)                  calendar += "闰" + MonthName[-1 * month].ToString() + "月";              else                  calendar += MonthName[month].ToString() + "月";                //农历日              calendar += DayName[day].ToString() + "日";                return calendar;                #endregion          }      }