做一个牛XX的身份证号验证类（支持15位和18位）

#region 是否合法的中国身份证号码      
        protected bool IsChineseID()
        {
            if (str.Length == 15)
                str = CidUpdate(str);
            if (str.Length == 18)
            {
                string strResult = CheckCidInfo(str);
                if (strResult == "非法地区" || strResult == "非法生日" || strResult == "非法证号")
                    return false;
                else
                    return true;
            }
            else
                return false;
        }
        #endregion

　　

#region 中国身份证号码验证
        private string CheckCidInfo(string cid)
        {
            string[] aCity = new string[] { null, null, null, null, null, null, null, null, null, null, null, "北京", "天津", "河北", "山西", "内蒙古", null, null, null, null, null, "辽宁", "吉林", "黑龙江", null, null, null, null, null, null, null, "上海", "江苏", "浙江", "安微", "福建", "江西", "山东", null, null, null, "河南", "湖北", "湖南", "广东", "广西", "海南", null, null, null, "重庆", "四川", "贵州", "云南", "西藏", null, null, null, null, null, null, "陕西", "甘肃", "青海", "宁夏", "新疆", null, null, null, null, null, "台湾", null, null, null, null, null, null, null, null, null, "香港", "澳门", null, null, null, null, null, null, null, null, "国外" };
            double iSum = 0;
            string info = string.Empty;
            System.Text.RegularExpressions.Regex rg = new System.Text.RegularExpressions.Regex(@"^\d{17}(\d|x)$");
            System.Text.RegularExpressions.Match mc = rg.Match(cid);
            if (!mc.Success)
                return string.Empty;
            cid = cid.ToLower();
            cid = cid.Replace("x", "a");
            if (aCity[int.Parse(cid.Substring(0, 2))] == null)
                return "非法地区";
            try
            {
                DateTime.Parse(cid.Substring(6, 4) + " - " + cid.Substring(10, 2) + " - " + cid.Substring(12, 2));
            }
            catch
            {
                return "非法生日";
            }
            for (int i = 17; i >= 0; i--)
                iSum += (System.Math.Pow(2, i) % 11) * int.Parse(cid[17 - i].ToString(), System.Globalization.NumberStyles.HexNumber);
            if (iSum % 11 != 1)
                return ("非法证号");
            else
                return (aCity[int.Parse(cid.Substring(0, 2))] + "," + cid.Substring(6, 4) + "-" + cid.Substring(10, 2) + "-" + cid.Substring(12, 2) + "," + (int.Parse(cid.Substring(16, 1)) % 2 == 1 ? "男" : "女"));
        }
        #endregion

　　

#region 身份证号码15升级为18位
        private string CidUpdate(string ShortCid)
        {
            char[] strJiaoYan = { '1', '0', 'X', '9', '8', '7', '6', '5', '4', '3', '2' };
            int[] intQuan = { 7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2, 1 };
            string strTemp;
            int intTemp = 0;
            strTemp = ShortCid.Substring(0, 6) + "19" + ShortCid.Substring(6);
            for (int i = 0; i <= strTemp.Length - 1; i++)
            {
                intTemp += int.Parse(strTemp.Substring(i, 1)) * intQuan[i];
            }
            intTemp = intTemp % 11;
            return strTemp + strJiaoYan[intTemp];
        }
        #endregion