C#实现单据号码的自动增加

给出一段代码，如：传入 MY00001   返回 MY00002  (逢十进一）

public string NextNumber(string BaseNumber)
        {
            string NewNumber = "";//新值
            int InNumber = 1;//进位
            int PlaceValue;//位值
            char[] No = BaseNumber.ToCharArray();

            for (int i = BaseNumber.Length - 1; i >= 0; i--)
            {
                if (No[i] == '9' && InNumber == 1)
                {
                    InNumber = 1;
                    NewNumber = "0" + NewNumber;
                }
                else
                 if (InNumber == 1 && No[i] >= '0' && No[i] < '9')
                {
                    PlaceValue = Int32.Parse(No[i].ToString());
                    PlaceValue = (InNumber + PlaceValue);
                    InNumber = 0;
                    NewNumber = PlaceValue.ToString() + NewNumber;
                }
                else
                {
                    InNumber = 0;
                    NewNumber = No[i] + NewNumber;
                }
            }
            if (BaseNumber == NewNumber)
                NewNumber = "00001";
            return NewNumber;
        }