无奈了 求高手帮忙 按要求写个算法

Question

FF2D00000002000010419000001AAAAA830702000A08140B11030303C0BA4048D0D76F180000B5000000033CFFFF2B00000002000010240000188AAAAA81200A08140B1B1D0303C011E6499096F51828003301000003F8FF 从版本号到数据字段的各个字节的不带进位累加和。计算时，先将校验和字段
填0x00，计算后，再将校验和写入该字段。
红色的是版本号
绿色的校验和

Answer 1

int length=data_lenth;      //假定为数据长度
byte checkcode=0;           //存储检验数据
for(int i=5;i<lenth-2;i++)  //5为起始计算位置
{
   checkcode+=Content[i];   //Content表示需要计算的字节数组
}
Content[lenth-2]=checkcode;大意如此

Answer 2

你确定你例子的校验和正确吗？
        private void button1_Click(object sender, EventArgs e)
        {
            //FF2D00000002000010419000001AAAAA830702000A08140B11030303C0BA4048D0D76F180000B5000000033CFF
            //FF2B00000002000010240000188AAAAA81200A08140B1B1D0303C011E6499096F51828003301000003F8FF
            //string strver = "FF2D00000002000010419000001AAAAA830702000A08140B11030303C0BA4048D0D76F180000B5000000033CFF";
            string strver = "FF2B00000002000010240000188AAAAA81200A08140B1B1D0303C011E6499096F51828003301000003F8FF";
            byte[] bver = new byte[strver.Length / 2];
            for (int i = 0; i < (strver.Length / 2); i++)
            {
                //倒数第二个字节为0
                if (i == (strver.Length / 2) - 2)
                {
                    bver[i] = 0;
                }
                else
                {
                    bver[i] = HexToByte(strver.Substring(i * 2, 2));
                }
            }
            bool blfind = false;
            byte icheck = 0;
            for (int i = 0; i < bver.Length; i++)
            {
                if (!blfind && bver[i] == 2)
                {
                    blfind = true;
                    icheck = bver[i];
                }
                if (blfind)
                {
                    icheck = (byte)(icheck + bver[i]);
                }
            }
            //倒数第二位填写校验和
            bver[(strver.Length / 2) - 2] = (byte)(0xff & icheck);
            string str = ToHexString(bver);
        }
        private static byte HexToByte(string hex)
        {
            if (hex.Length > 2 || hex.Length <= 0)                throw new ArgumentException("hex must be 1 or 2 characters in length");            byte newByte = byte.Parse(hex, System.Globalization.NumberStyles.HexNumber);            return newByte;        }
        private static string ToHexString(byte[] bytes) 
        {
            string hexString = string.Empty;
            if (bytes != null)
            {
                StringBuilder strB = new StringBuilder();                for (int i = 0; i < bytes.Length; i++)
                {
                    strB.Append(bytes[i].ToString("X2"));
                }
                hexString = strB.ToString();
            }
            return hexString;
        }

Answer 3

最后icheck不用“与”了，当时icheck定义的是int所以用了“与”
bver[(strver.Length / 2) - 2] =  icheck;
str就是含校验码的返回值
  string str = ToHexString(bver);

Answer 4

修正一个地方
            for (int i = 0; i < bver.Length; i++)
            {
                if (!blfind && bver[i] == 2)
                {
                    blfind = true;
                    icheck = bver[i];
                }
                if (blfind)
                {
                    icheck = (byte)(icheck + bver[i]);
                }
            }
应该为
            for (int i = 0; i < bver.Length; i++)
            {
                if (!blfind && bver[i] == 2)
                {
                    blfind = true;
                }
                if (blfind)
                {
                    icheck = (byte)(icheck + bver[i]);
                }
            }
不然会重复加了个2循环次数是bver.Length和bver.Length-1没有区别，因为最后一个字节FF不会影响计算