c#验证身份证号

using System;using System.Collections.Generic;using System.Text;namespace IDprocess{    class Program    {        static void Main(string[] args)        {            Console.Write("请输入身份证号：");            string idnumber = Console.ReadLine().Trim();            ID oneID = new ID(idnumber);            if (oneID.IsValid())                Console.WriteLine("您的出生日期是：" + oneID.getBirthday().ToString("yyyy年M月d日"));            else                Console.WriteLine("对不起，身份证号码错误！");            Console.Read();        }    }    class ID    {        private string IDnumber;        public ID(string idnumber)        {            this.IDnumber = idnumber.Trim();        }        //判断是否为有效的身份证号码：        public bool IsValid()        {            int year, month,day ;            if (IDnumber.Length == 15)            {                for (int i = 0; i < 15; i++)                {                    //如果有非数字，则无效，返回false                    if (!char.IsNumber(IDnumber[i]))                    {                        return false;                    }                }                //取得出生年月日：                year = Int32.Parse("19" + IDnumber.Substring(6, 2));                month = Int32.Parse(IDnumber.Substring(8, 2));                day = Int32.Parse(IDnumber.Substring(10, 2));                //调用方法IsValidBirthday判断是否为有效的出生年月日：                return IsValidBirthday(year, month, day);            }            else if (IDnumber.Length == 18)            {                for (int i = 0; i < 17; i++)                {                    if (!char.IsNumber(IDnumber[i]))                    {                        return false;                    }                }                if (!char.IsNumber(IDnumber[17]) && IDnumber[17] != 'X')                    return false;                //取得出生年月日：                year = Int32.Parse(IDnumber.Substring(6,4));                month = Int32.Parse(IDnumber.Substring(10, 2));                day = Int32.Parse(IDnumber.Substring(12, 2));  //调用方法IsValidBirthday判断是否为有效的出生年月日：                return IsValidBirthday(year, month, day);            }            else                return false;                    }        //判断是否为有效的出生年月日：        private bool IsValidBirthday(int year,int  month,int day)        {            if(year==0)                 return false;            if (month<1||month > 12)                return false;            //判断天数是否在指定年和月中所限制的天数范围之内。            if (day < 1 || day > DateTime.DaysInMonth(year, month))                return false;            //判断出生日期是否大于现在的日期。            DateTime Birthday = new DateTime(year, month, day);            if (Birthday > DateTime.Now)               return false;           return true;        }       //获取出生日期        public DateTime getBirthday()       {            DateTime  Birthday;           int year, month,day ;           if (IsValid())           {               if (IDnumber.Length == 15)               {                 year = Int32.Parse("19" + IDnumber.Substring(6, 2));                 month = Int32.Parse(IDnumber.Substring(8, 2));                 day = Int32.Parse(IDnumber.Substring(10, 2));                  Birthday = new DateTime(year, month, day);               }                               else                {                  year = Int32.Parse(IDnumber.Substring(6, 4));                 month = Int32.Parse(IDnumber.Substring(10, 2));                 day = Int32.Parse(IDnumber.Substring(12, 2));                        Birthday = new DateTime(year, month, day);               }           }           else Birthday = new DateTime(1, 1, 1);           return Birthday;       }    }}