Gino的筆記本

今天用C#寫了一個身分證驗證程式，因為剛學可能寫得不好，如果哪邊可以改進請大家告知一下，謝謝!

public static bool CheckID(string sid)
        {

            string[] sid_array = new string[10];
           
            int[] int_array = { 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33 };

            if (sid.Length != 10)
            {
                return false;
            }
            else
            {
                sid = sid.ToUpper();

                for (int i = 0; i <= (sid.Length - 1); i++)
                {
                    sid_array[i] = sid.Substring(i, 1);
                }

                int first_array = (ascii(sid_array[0]) - 65);


                int checktotal = Convert.ToInt16(int_array[first_array].ToString().Substring(0, 1)) + (Convert.ToInt16(int_array[first_array].ToString().Substring(1, 1)) * 9);

                for (int j = 1; j < 9; j++)
                {
                    checktotal = checktotal + Convert.ToInt16(sid_array[j]) * (9 - j);

                }

                int checksum = (checktotal % 10);

                if (checksum == 0)
                {
                    checksum = 0;
                }
                else
                {
                    checksum = int_array[first_array] - checksum;
                }


                if (checksum == Convert.ToInt16(sid_array[9]))
                {
                    return true ;
                }
                else
                {
                    return false;
                }

            }
                              
        }

下面的部分是類似VB ASC函數的功能，因為我找不到C#要如何寫，這是在網路上找到的

http://blog.csdn.net/hongsejiaozhu/archive/2008/03/03/2142473.aspx

public static int ascii(string chr)
        {
            Encoding ecode = Encoding.GetEncoding("big5");
            byte[] codebytes = ecode.GetBytes(chr.ToString());
 
            if (istwobyteschar(chr))
            {
                return (int)codebytes[0] * 256 + (int)codebytes[1] - 65536;
            }
            else
            {
                return (int)codebytes[0];
            }
        }

 public static bool istwobyteschar(string chr)
        {
            string str = chr.ToString();

            Encoding ecode = Encoding.GetEncoding("big5");
            if (ecode.GetByteCount(str) == 2)
            {
                return true;
            }
            else
            {
                return false;
            }
        }