网站上显示农历及阳历节日

把阳历日期转换为农历用到的函数为ChinaDate.ConvertToNongLi(DateTime.Now);

得到节日的函数为 ChinaDate.GetFestival(DateTime.Now);

代码：

using System.Globalization;
using System.Collections;
using System;

namespace NetWeb2011.Common
{
    public static class ChinaDate
    {
        private static ChineseLunisolarCalendar china = new ChineseLunisolarCalendar();
        private static Hashtable gHoliday = new Hashtable();
        private static Hashtable nHoliday = new Hashtable();
        private static string[] JQ = { "小寒", "大寒", "立春", "雨水", "惊蛰", "春分", "清明", "谷雨", "立夏", "小满", "芒种", "夏至", "小暑", "大暑", "立秋", "处暑", "白露", "秋分", "寒露", "霜降", "立冬", "小雪", "大雪", "冬至" };
        private static int[] JQData = { 0, 21208, 43467, 63836, 85337, 107014, 128867, 150921, 173149, 195551, 218072, 240693, 263343, 285989, 308563, 331033, 353350, 375494, 397447, 419210, 440795, 462224, 483532, 504758 };

        static ChinaDate()
        {
            //公历节日
            gHoliday.Add("0101", "元旦");
            gHoliday.Add("0214", "情人节");
            gHoliday.Add("0305", "雷锋日");
            gHoliday.Add("0308", "妇女节");
            gHoliday.Add("0312", "植树节");
            gHoliday.Add("0315", "消费者权益日");
            gHoliday.Add("0401", "愚人节");
            gHoliday.Add("0405", "清明节");
            gHoliday.Add("0501", "劳动节");
            gHoliday.Add("0504", "青年节");
            gHoliday.Add("0601", "儿童节");
            gHoliday.Add("0701", "建党节");
            gHoliday.Add("0801", "建军节");
            gHoliday.Add("0910", "教师节");
            gHoliday.Add("1001", "国庆节");
            gHoliday.Add("1031", "万圣节");
            gHoliday.Add("1224", "平安夜");
            gHoliday.Add("1225", "圣诞节");

            //农历节日
            nHoliday.Add("0101", "春节");
            nHoliday.Add("0115", "元宵节");
            nHoliday.Add("0505", "端午节");
            nHoliday.Add("0815", "中秋节");
            nHoliday.Add("0909", "重阳节");
            nHoliday.Add("1208", "腊八节");
            nHoliday.Add("1230", "大年三十");
        }

        /// <summary>
        /// 获取农历
        /// </summary>
        /// <param name="dt"></param>
        /// <returns></returns>
        public static string GetChinaDate(DateTime dt)
        {
            if (dt > china.MaxSupportedDateTime || dt < china.MinSupportedDateTime)
            {
                //日期范围：1901 年 2 月 19 日 - 2101 年 1 月 28 日
                throw new Exception(string.Format("日期超出范围！必须在{0}到{1}之间！", china.MinSupportedDateTime.ToString("yyyy-MM-dd"), china.MaxSupportedDateTime.ToString("yyyy-MM-dd")));
            }
            string str = string.Format("{0} {1}{2}", GetYear(dt), GetMonth(dt), GetDay(dt));
            string strJQ = GetSolarTerm(dt);
            if (strJQ != "")
            {
                str += " (" + strJQ + ")";
            }
            string[] strHoliday = GetHoliday(dt, 0);
            if (strHoliday != null)
            {
                str += " " + strHoliday;
            }
            string[] strChinaHoliday = GetChinaHoliday(dt, 0);
            if (strChinaHoliday != null)
            {
                str += " " + strChinaHoliday;
            }

            return str;
        }

        /// <summary>
        /// 获取农历年份
        /// </summary>
        /// <param name="dt"></param>
        /// <returns></returns>
        public static string GetYear(DateTime dt)
        {
            int yearIndex = china.GetSexagenaryYear(dt);
            string yearTG = " 甲乙丙丁戊己庚辛壬癸";
            string yearDZ = " 子丑寅卯辰巳午未申酉戌亥";
            string yearSX = " 鼠牛虎兔龙蛇马羊猴鸡狗猪";
            int year = china.GetYear(dt);
            int yTG = china.GetCelestialStem(yearIndex);
            int yDZ = china.GetTerrestrialBranch(yearIndex);

            string str = string.Format("[{1}]{2}{3}{0}", year, yearSX[yDZ], yearTG[yTG], yearDZ[yDZ]);
            return str;
        }
        /// <summary>
        /// 得到公历所对应的农历年
        /// </summary>
        /// <param name="dt"></param>
        /// <returns></returns>
        public static string GetChinaYear(DateTime dt)
        {
            return china.GetYear(dt).ToString();
        }

        /// <summary>
        /// 获取农历月份
        /// </summary>
        /// <param name="dt"></param>
        /// <returns></returns>
        public static string GetMonth(DateTime dt)
        {
            int year = china.GetYear(dt);
            int iMonth = china.GetMonth(dt);
            int leapMonth = china.GetLeapMonth(year);
            bool isLeapMonth = iMonth == leapMonth;
            if (leapMonth != 0 && iMonth >= leapMonth)
            {
                iMonth--;
            }

            string szText = "正二三四五六七八九十";
            string strMonth = isLeapMonth ? "闰" : "";
            if (iMonth <= 10)
            {
                strMonth = "";
                strMonth = strMonth + szText.Substring(iMonth - 1, 1);
            }
            else if (iMonth == 11)
            {
                strMonth = "十一";
            }
            else
            {
                strMonth = "腊";
            }
            return strMonth + "月";
        }

        /// <summary>
        /// 获取农历日期
        /// </summary>
        /// <param name="dt"></param>
        /// <returns></returns>
        public static string GetDay(DateTime dt)
        {
            int iDay = china.GetDayOfMonth(dt);
            string szText1 = "初十廿三";
            string szText2 = "一二三四五六七八九十";
            string strDay;
            if (iDay == 20)
            {
                strDay = "二十";
            }
            else if (iDay == 30)
            {
                strDay = "三十";
            }
            else
            {
                strDay = szText1.Substring((iDay - 1) / 10, 1);
                strDay = strDay + szText2.Substring((iDay - 1) % 10, 1);
            }
            return strDay;
        }
        private static string GetNongLiDay(string str)
        {
            string ret = string.Empty;
            ret += ConvertNongliToDigital(str.Substring(0, 1), 0);
            ret += ConvertNongliToDigital(str.Substring(1, 1), 1);
            return ret;
        }

        private static string GetNongLiMonth(string str)
        {
            string ret = string.Empty;
            if (str.Length == 2) //是 十月 还是 十一月
            {
                ret += ConvertMonthToDigital(str.Substring(0, 1));
                ret += ConvertMonthToDigital(str.Substring(1, 1));
            }
            else if (str.Length == 3)
            {
                ret += ConvertMonthToDigital(str.Substring(0, 2));
            }

            return ret;
        }
        /// <summary>
        /// 把汉字月转换成对应的数字
        /// </summary>
        /// <param name="nonglimonth"></param>
        /// <returns></returns>
        private static string ConvertMonthToDigital(string nonglimonth)
        {
            string ret = string.Empty;
            switch (nonglimonth)
            {
                case "一": ret = "1";
                    break;
                case "二": ret = "2";
                    break;
                case "三": ret = "3";
                    break;
                case "四": ret = "4";
                    break;
                case "五": ret = "5";
                    break;
                case "六": ret = "6";
                    break;
                case "七": ret = "7";
                    break;
                case "八": ret = "8";
                    break;
                case "九": ret = "9";
                    break;
                case "十":
                    ret = "10";
                    break;
                case "十一":
                    ret = "11";
                    break;
                case "十二":
                    ret = "12";
                    break;
                case "正":
                    ret = "1";
                    break;
                case "腊":
                    ret = "12";
                    break;
            }
            return ret;
        }
        /// <summary>
        /// 把汉字日转换成对应的数字，first，是用来区别十这个汉字，是在第一个位置还是在别的位置上
        /// </summary>
        /// <param name="nongli"></param>
        /// <param name="first"></param>
        /// <returns></returns>
        private static string ConvertNongliToDigital(string nongli, int first)
        {
            string ret = string.Empty;
            switch (nongli)
            {
                case "一": ret = "1";
                    break;
                case "二": ret = "2";
                    break;
                case "三": ret = "3";
                    break;
                case "四": ret = "4";
                    break;
                case "五": ret = "5";
                    break;
                case "六": ret = "6";
                    break;
                case "七": ret = "7";
                    break;
                case "八": ret = "8";
                    break;
                case "九": ret = "9";
                    break;
                case "十":
                    if (first == 1)
                    {
                        ret = "0";
                    }
                    else ret = "1";
                    break;
                case "初": ret = "0";
                    break;
                case "廿": ret = "2";
                    break;
            }
            return ret;
        }
        /// <summary>
        /// 获取节气
        /// </summary>
        /// <param name="dt"></param>
        /// <returns></returns>
        public static string GetSolarTerm(DateTime dt)
        {
            DateTime dtBase = new DateTime(1900, 1, 6, 2, 5, 0);
            DateTime dtNew;
            double num;
            int y;
            string strReturn = "";

            y = dt.Year;
            for (int i = 1; i <= 24; i++)
            {
                num = 525948.76 * (y - 1900) + JQData[i - 1];
                dtNew = dtBase.AddMinutes(num);
                if (dtNew.DayOfYear == dt.DayOfYear)
                {
                    strReturn = JQ[i - 1];
                }
            }

            return strReturn;
        }
        /// <summary>
        /// 获取公历节日
        /// </summary>
        /// <param name="dt"></param>
        /// <returns></returns>
        public static string[] GetHoliday(DateTime dt, int next) //next为0表示当前月，next为1表示下个月
        {
            string strReturn = "";
            object g = null;
            if (next == 0)
            {
                g = gHoliday[dt.Month.ToString("00") + dt.Day.ToString("00")];
            }
            if (g != null)
            {
                strReturn = g.ToString();
                return new string[] { dt.Month.ToString("00") + dt.Day.ToString("00"), g.ToString() };
            }
            else
            {
                string first = string.Empty;
                int day = 0;//当前多少号
                if (next == 0)
                {
                    first = dt.Month.ToString("00");
                    day = dt.Day; //当前多少号
                }
                else
                {
                    dt = dt.AddMonths(next);
                    first = dt.Month.ToString("00");
                }
                day++;
                for (int i = day; i <= 31; i++)
                {
                    object festival = gHoliday[first + i.ToString("00")];
                    if (festival != null)
                    {
                        string[] ret = { first + i.ToString("00"), festival.ToString() }; //当前当月的离今天最近的一个节日
                        return ret;
                    }
                }
            }
            return null;
        }

        /// <summary>
        ///  获取农历节日
        /// </summary>
        /// <param name="dt"></param>
        /// <returns></returns>
        public static string[] GetChinaHoliday(DateTime dt, int next) //next表示是否是下一个月
        {
            string strReturn = string.Empty;

            int year = china.GetYear(dt);
            int iMonth = china.GetMonth(dt);
            int leapMonth = china.GetLeapMonth(year);
            int iDay = china.GetDayOfMonth(dt);
            if (china.GetDayOfYear(dt) == china.GetDaysInYear(year))
            {
                strReturn = "除夕";
            }
            else if (leapMonth != iMonth)
            {
                if (leapMonth != 0 && iMonth >= leapMonth)
                {
                    iMonth--;
                }
                object n = nHoliday[iMonth.ToString("00") + iDay.ToString("00")];
                if (n != null)
                {
                    string[] ret = { iMonth.ToString("00") + iDay.ToString("00"), n.ToString() };
                    return ret;
                }
                else  //该日期没有节日
                {
                    if (next != 0)
                    {
                        iDay = 0;
                        iMonth += next;
                    }
                    for (int i = iDay; i <= 31; i++)
                    {
                        object festival = nHoliday[iMonth.ToString("00") + i.ToString("00")];
                        if (festival != null)
                        {
                            string[] ret = { iMonth.ToString("00") + i.ToString("00"), festival.ToString() };
                            return ret;
                        }
                    }
                }
            }
            if (strReturn != string.Empty)
            {
                return new string[] { "1230", "除夕" };
            }
            return null;
        }
        /// <summary>
        /// 把阳历转成农历
        /// </summary>
        /// <param name="dt"></param>
        /// <returns></returns>
        public static DateTime ConvertToNongLi(DateTime dt)
        {
            string year = ChinaDate.GetChinaYear(dt);
            string month = ChinaDate.GetNongLiMonth(ChinaDate.GetMonth(dt));
            string day = ChinaDate.GetNongLiDay(ChinaDate.GetDay(dt));
            DateTime dtnongli = DateTime.Parse(year + "-" + month + "-" + day);
            return dtnongli;
        }
        /// <summary>
        /// 得到节日，没有节日的话，就返回empty
        /// </summary>
        /// <param name="dt"></param>
        /// <returns></returns>
        public static string GetFestival(DateTime dt)
        {
            try
            {
                string currentfestival = string.Empty;
                string nonglidate = string.Empty;
                string gonglidate = string.Empty;
                int distance = 0;

                int basemonth = 0;
                string[] gongli = ChinaDate.GetHoliday(dt, basemonth);//公历节日
                string[] nongli = ChinaDate.GetChinaHoliday(dt, basemonth);//农历节日

                bool festival = true; //是否这个月内有节日

                DateTime dtGongli = dt;
                DateTime dtNongli = dt;

                if (gongli == null && nongli == null) //如果同时为空，就取下个月的
                {
                    basemonth++;
                    gongli = ChinaDate.GetHoliday(dt, basemonth);//公历节日
                    nongli = ChinaDate.GetChinaHoliday(dt, basemonth);//农历节日
                }
                //dt = dt.AddMonths(basemonth);

                if (gongli != null)
                {
                    DateTime riqi = DateTime.Parse(dt.Year.ToString() + "-" + gongli[0].Substring(0, 2) + "-" + gongli[0].Substring(2, 2));
                    dtGongli = ConvertToNongLi(riqi);
                }
                if (nongli != null)
                {
                    dtNongli = DateTime.Parse(ChinaDate.GetChinaYear(dt) + "-" + nongli[0].Substring(0, 2) + "-" + nongli[0].Substring(2, 2));
                }

                System.Text.StringBuilder today = new System.Text.StringBuilder();

                //today.Append(DateTime.Now.ToString("yyyy-MM-dd") + " " + DateTime.Now.ToString("ddd", new System.Globalization.CultureInfo("zh-cn")) + "  ");
                if (gongli != null && nongli != null)
                {
                    TimeSpan ts = dtGongli - dtNongli;
                    if (ts.Days < 0)// 公历的节日更近 把两个日期都转换成公历进行比较
                    {
                        currentfestival = gongli[1];
                        gonglidate = gongli[0];
                        TimeSpan tsDay = dtGongli - ConvertToNongLi(dt);
                        distance = tsDay.Days;
                    }
                    else
                    {
                        ts = dtNongli - dtGongli;
                        currentfestival = nongli[1];
                        TimeSpan tsDay = dtNongli - ConvertToNongLi(dt);
                        distance = tsDay.Days;
                    }
                }
                else if (gongli != null)
                {
                    currentfestival = gongli[1];
                    DateTime dtfestival = ConvertToNongLi(DateTime.Parse(ChinaDate.GetChinaYear(dt) + "-" + gongli[0].Substring(0, 2) + "-" + gongli[0].Substring(2, 2)));

                    TimeSpan tsDay = dtfestival - ConvertToNongLi(dt);
                    distance = tsDay.Days;
                }
                else if (nongli != null)
                {
                    currentfestival = nongli[1];
                    distance = int.Parse(nongli[0].Substring(2, 2)) - ConvertToNongLi(dt).Day;
                }
                else festival = false;
                //today.Append("农历" + ChinaDate.GetMonth(dt) + ChinaDate.GetDay(dt));

                if (festival)
                {
                    if (distance > 0)
                        today.Append(" 离<font color='red'>" + currentfestival + "</font>还有<font color='red'>" + distance + "</font>天   ");
                    else today.Append(" 今天是 <font color='red'>" + currentfestival + "</font>   ");
                }
                //else today.Append("  ");

                return today.ToString();
            }
            catch
            {
                return string.Empty;
            }
        }
    }
}