[转]常用函数集(检验日期，身份证十五位身份证为十八位，得到字符的ASCII码)

 /**//// <summary>
        /// 检验日期格式是否正确
        /// </summary>
        public string IsDateFormat(string strDate)#region public string IsDateFormat(string strDate)
        public string IsDateFormat(string strDate)
        {
            strDate = strDate.Trim();

            Regex r1 = new Regex(@"^(?<year>[1-9][0-9]{0,3})/(?<month>[0-9]{1,2})/(?<day>[0-9]{1,2})$");
            Regex r2 = new Regex(@"^(?<year>[1-9][0-9]{0,3})-(?<month>[0-9]{1,2})-(?<day>[0-9]{1,2})$");
            Regex r3 = new Regex(@"^(?<year>[1-9][0-9]{0,3})年(?<month>[0-9]{1,2})月(?<day>[0-9]{1,2})日$");
            Regex r4 = new Regex(@"^(?<month>[0-9]{1,2})/(?<day>[0-9]{1,2})/(?<year>[1-9][0-9]{0,3})$");

            // 取得日期的年，月，日
            string year, month, date;

            if(Regex.IsMatch(strDate,@"^(?<month>[0-9]{1,2})/(?<day>[0-9]{1,2})/(?<year>[1-9][0-9]{3})$"))
            {
                year = r4.Match(strDate).Result("${year}");
                month = r4.Match(strDate).Result("${month}");
                date = r4.Match(strDate).Result("${day}");
            }
            else if (Regex.IsMatch(strDate,@"^(?<year>[1-9][0-9]{0,3})/(?<month>[0-9]{1,2})/(?<day>[0-9]{1,2})$"))
            {
                year = r1.Match(strDate).Result("${year}");
                month = r1.Match(strDate).Result("${month}");
                date = r1.Match(strDate).Result("${day}");
            }
            else if(Regex.IsMatch(strDate,@"^(?<year>[1-9][0-9]{0,3})-(?<month>[0-9]{1,2})-(?<day>[0-9]{1,2})$"))
            {
                year = r2.Match(strDate).Result("${year}");
                month = r2.Match(strDate).Result("${month}");
                date = r2.Match(strDate).Result("${day}");
            }
            else if(Regex.IsMatch(strDate,@"^(?<year>[1-9][0-9]{0,3})年(?<month>[0-9]{1,2})月(?<day>[0-9]{1,2})日$"))
            {
                year = r3.Match(strDate).Result("${year}");
                month = r3.Match(strDate).Result("${month}");
                date = r3.Match(strDate).Result("${day}");
            }            
            else
            {
                return "error";
            }

            // 最后检查日期的正确性
            try
            {
                System.DateTime dt = new DateTime(Convert.ToInt32(year), Convert.ToInt32(month), Convert.ToInt32(date));
                return dt.ToString("yyyy-MM-dd");
            }
            catch
            {
                return "error";
            }
        }
        #endregion

        ------------------------------------------------------------------------------------------

        /**//// <summary>
        /// 检验Email字符串格式是否正确
        /// </summary>
        public bool IsEmailFormat(string strEmail)#region public bool IsEmailFormat(string strEmail)
        public bool IsEmailFormat(string strEmail)
        {
            return Regex.IsMatch(strEmail, @"^([\w-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([\w-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$");
        }
        #endregion

        ------------------------------------------------------------------------------------------


        /**//// <summary>
        /// 转换十五位身份证为十八位的函数。
        /// </summary>
        public string ConvertIDCard15to18(string strTemp)#region public string ConvertIDCard15to18(string strTemp)
        public string ConvertIDCard15to18(string strTemp)
        {
            int[] arrInt = new int[]{7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2};
            string arrCh="10X98765432";
            int nTemp = 0;
            if(strTemp.Length==15)
            {
                strTemp = strTemp.Substring(0,6) + "19" + strTemp.Substring(6,strTemp.Length-6);
                for(int i = 0; i < strTemp.Length; i++)
                {
                    nTemp += int.Parse(strTemp.Substring(i, 1).ToString()) * arrInt[i];
                }
                strTemp += arrCh[nTemp % 11]; 
            }
            char dd=arrCh[nTemp % 11]; 
            return strTemp;
        } 
        #endregion
        
        ------------------------------------------------------------------------------------------

        下在为判断ASCII码的函数组，仅支持中英文

        /**//// <summary>
        /// 是否为双字节字符。
        /// </summary>
        public static bool IsTwoBytesChar(char chr)
        {
            string str =chr.ToString();
            // 使用中文支持编码
            Encoding ecode = Encoding.GetEncoding("GB18030");
            if (ecode.GetByteCount(str) == 2)
            {
                return true;
            }
            else
            {
                return false;
            }
        }

        /**//// <summary>
        /// 得到字符的ASCII码
        /// </summary>
        public static int ASCII(char chr)
        {
            Encoding ecode = Encoding.GetEncoding("GB18030");
            Byte[] codeBytes = ecode.GetBytes(chr.ToString());
            if ( IsTwoBytesChar(chr) )
            {
                // 双字节码为高位乘256，再加低位
                // 该为无符号码，再减65536
                return (int)codeBytes[0] * 256 + (int)codeBytes[1] - 65536;
            }
            else
            {
                return (int)codeBytes[0];
            }
        }