C#中十六进制相加问题

Question

                                            CRCchange = s.Substring(count3,count4-count3+1);
                                            byte[] arr = new byte[] { };
                                            string[] str=new string[arr.Length];
                                            arr=Encoding.ASCII.GetBytes(CRCchange);
                                            for (int i = 0; i < arr.Length;i++ )
                                            {
                                                str[i] = arr[i].ToString("X2"+"");
                                            }
                                            CRCchange =str.ToString();上边代码要实现功能：截取字符串中的数据，按字节存储在数组中，然后再按字节输出十六进制的数，存放在数组str中，然后再让str数组中的每一项都加上一个十六进制常量应该怎么写？是 str[i] = arr[i].ToString("X2"+"0x30");吗？

Answer 1

http://www.google.com.hk/search?hl=zh-CN&source=hp&q=C%23%E4%B8%AD%E5%8D%81%E5%85%AD%E8%BF%9B%E5%88%B6%E7%9B%B8%E5%8A%A0&gbv=2&oq=C%23%E4%B8%AD%E5%8D%81%E5%85%AD%E8%BF%9B%E5%88%B6%E7%9B%B8%E5%8A%A0&aq=f&aqi=&aql=&gs_l=hp.3...563.3313.0.5016.2.2.0.0.0.0.109.187.1j1.2.0...0.0.YBjfO6AMRLkhttp://hphubei.itpub.net/post/2868/304738
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Answer 2

http://www.google.com.hk/search?hl=zh-CN&source=hp&q=C%23%E4%B8%AD%E5%8D%81%E5%85%AD%E8%BF%9B%E5%88%B6%E7%9B%B8%E5%8A%A0&gbv=2&oq=C%23%E4%B8%AD%E5%8D%81%E5%85%AD%E8%BF%9B%E5%88%B6%E7%9B%B8%E5%8A%A0&aq=f&aqi=&aql=&gs_l=hp.3...563.3313.0.5016.2.2.0.0.0.0.109.187.1j1.2.0...0.0.YBjfO6AMRLkhttp://hphubei.itpub.net/post/2868/304738
学会搜索

Answer 3

str[i] = arr[i].ToString("X2"+"");
=>
str[i] = (arr[i] + 0x30).ToString("X2");
不过要考虑溢出。最好这么写：
str[i] = ((arr[i] + 0x30) % 256).ToString("X2");

Answer 4

您好，我改过的代码是                                            string CRCchange;
                                            CRCchange = s.Substring(count3,count4-count3+1);
                                            byte[] arr = new byte[] { };
                                            string[] str=new string[arr.Length];
                                            arr=Encoding.ASCII.GetBytes(CRCchange);
                                            for (int i = 0; i < arr.Length;i++ )
                                            {
                                                str[i] = ((arr[i]+0x30)%256).ToString("X2");
                                                richTextBox1.AppendText(str[i]);
                                            }
加入代码之后为什么在richtextbox1中没有数据显示出来呢？
而且还影响其它代码的运行取值呢

Answer 5

richTextBox1.AppendText(str[i]);=>
richTextBox1.Text += str[i];