Verify the legitimacy of the ID card

/// </summary>  
        /// <param name="Id"></param>  
        /// <returns></returns>  
        public bool CheckIDCard(string idNumber)
        {
            if (idNumber.Length == 18)
            {
                bool check = CheckIDCard18(idNumber);
                return check;
            }
            else
            {
                return false;
            }
        }

        ///  <summary> 
        /// 18-digit ID number verification
         ///  </summary> 
        ///  <param name="idNumber"></param> 
        ///  <returns></returns> 
        public  bool CheckIDCard18 ( string idNumber)
        {
            long n = 0;
            if (long.TryParse(idNumber.Remove(17), out n) == false || n < Math.Pow(10, 16) || long.TryParse(idNumber.Replace('x', '0').Replace('X', '0'), out n) == false)
            {
                return false;//数字验证  
            }
            string address = "11x22x35x44x53x12x23x36x45x54x13x31x37x46x61x14x32x41x50x62x15x33x42x51x63x21x34x43x52x64x65x71x81x82x91";
            if (address.IndexOf(idNumber.Remove(2)) == -1)
            {
                return  false ; // province verification   
            }
             string birth = idNumber.Substring( 6 , 8 ).Insert( 6 , " - " ).Insert( 4 , " - " );
            DateTime time = new DateTime();
            if (DateTime.TryParse(birth, out time) == false)
            {
                return false;//生日验证  
            }
            string[] arrVarifyCode = ("1,0,x,9,8,7,6,5,4,3,2").Split(',');
            string[] Wi = ("7,9,10,5,8,4,2,1,6,3,7,9,10,5,8,4,2").Split(',');
            char[] Ai = idNumber.Remove(17).ToCharArray();
            int sum = 0;
            for (int i = 0; i < 17; i++)
            {
                sum += int.Parse(Wi[i]) * int.Parse(Ai[i].ToString());
            }
            int y = -1;
            Math.DivRem(sum, 11, out y);
            Console.WriteLine("Y的理论值: " + y);
            if (arrVarifyCode[y] != idNumber.Substring(17, 1).ToLower())
            {
                return  false ; // Check code verification   
            }
             return  true ; // Compliant with GB11643-1999 standard   
        }