代码生成组合编码

简单介绍：
         有一主键列ID  ，类型Char(5).
         现在要写一个方法来获得下一递增的编码，并进行存储。
         大体规则如下描述：

        /**
         *      ID      |       Name
         *      00000   |       jim
         *      00001   |       jacky
         *      00002   |       jiles
         *                   
         *      99999   |       ???
         *      A0000   |       ???
         *                   
         *      A9999   |       ???
         *      B0000   |       ???
         *                   
         *      Z9999   |       ???
         *      ZA000   |       ???
         *                   
         *      ZZZZZ   |       end
         * 
         * */

代码：( Jim 亮哥提供)

#region 自动生成下一编码
        public static string Gen(string lastId)
        {

                //1.定位最高增位index

                Regex rx = new Regex(@"[0-9A-Y]");
                Match match = rx.Match(lastId);
                int incIndex = match.Index;

                //如果没有找到 incIndex=-1;
                if (!match.Success)
                {                     
                    throw new ArgumentException("已达到最高值，参数错误，无法递增");
                }                

                //最前面的字符串.
                string topString = lastId.Substring(0, incIndex);
                //其它位字符串,                
                string otherString = lastId.Substring(incIndex + 1);

                //如果没有其它位了
                if (otherString == String.Empty)
                {
                    char incChar = (lastId[incIndex] == '9') ? 'A' : (char)(lastId[incIndex] + 1);
                    return topString + incChar;                    
                }


               
                int otherlen = otherString.Length;
                int otherNumber = int.Parse(otherString);// int->long  可以达到更大的位数



                //2.其它位做加1运算 
                otherNumber += 1;

                string result = "";
                string newOtherString = otherNumber.ToString();
                
               
                if (otherNumber <(int) Math.Pow(10.0, (double)otherlen))// int->long
                {
                    char incChar = lastId[incIndex];
                    result = topString + incChar + newOtherString.PadLeft(otherlen, '0');
                }
                else
                {
                    char incChar = (lastId[incIndex]=='9')?'A':(char)(lastId[incIndex] + 1);
                    result = topString + incChar + newOtherString.Substring(1);
                    Console.WriteLine(topString);
                }
                return result;
        }
        #endregion