根据出生日期计算年龄

 /// <summary>
    /// 根据出生日期计算年龄 

    /// </summary>
    /// <param name="dtNow">当前时间</param>
    /// <param name="dtDOB">出生日期</param>
    /// <returns></returns>
     public static string GetAge(DateTime dtNow,DateTime dtBirthday)
     {
            string  strAge      = string.Empty;                         // 年龄的字符串表示
            int     intYear     = 0;                                    // 岁
            int     intMonth    = 0;                                    // 月
            int     intDay      = 0;                                    // 天
            // 计算天数
            intDay = dtNow.Day - dtBirthday.Day;
            if (intDay < 0)
            {
                dtNow = dtNow.AddMonths(-1);
                intDay += DateTime.DaysInMonth(dtNow.Year, dtNow.Month);
            }
            // 计算月数
            intMonth = dtNow.Month - dtBirthday.Month;
            if (intMonth < 0)
            {
                intMonth += 12;
                dtNow = dtNow.AddYears(-1);
            }
            // 计算年数
            intYear = dtNow.Year - dtBirthday.Year;
            // 格式化年龄输出
            if (intYear >= 1)                                            // 年份输出
            {
                strAge = intYear.ToString() + "岁";
            }
            if (intMonth > 0 && intYear <1)                           // 1岁以下可以输出月数
            {
                strAge += intMonth.ToString() + "月";
            }
            if (intDay >= 0 && intMonth < 1)                              // 1个月以下可以输出天数
            {
                if (strAge.Length == 0 || intDay > 0)
                {
                    strAge += intDay.ToString() + "天";
                }
            }
            return strAge;
        }

直接调用方法就可以了。