C# 16进制字节转Int（涉及：Base64转byte数组）

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一个字节数组，如下：

 List<byte> by2 = new List<byte>() {0x55,0x22 };//8789

其对应的十进制的值为：8789

 从上图可知，C#中byte数组默认为低字节在前

再例如：

List<byte> by3 = new List<byte>() { 0x55, 0x22 ,0x11};//1122901

对应的十进制是：1122901

对应的16进制为：0x112255，如下：

 经过上述两个案例，C#byte数组中是按照低字节在前的方式排列的。

C#中有什么方法转化字节流为Int吗？

            List<byte> by2 = new List<byte>() {0x55,0x22 };//8789
            int ResultInt16 = BitConverter.ToInt16(by2.ToArray(), 0);
            List<byte> by4 = new List<byte>() { 0x55, 0x22, 0x11, 0x01 };//1428295937 
            int ResultInt32 = BitConverter.ToInt32(by4.ToArray(), 0);

涉及到两个方法：BitConverter.ToInt16 和 BitConverter.ToInt32

但是：：BitConverter.ToInt这个方法只能转化长度为2或者长度为4的字节数组，如果字节长度为3，则无法转化。

譬如：

 List<byte> by3 = new List<byte>() { 0x55, 0x22 ,0x11};//1122901

因此，有必要做一个通用方法

在实际业务需求中，软硬件双方制定的通讯协议中经常为字节流指定是高字节在前？还是低字节在前？

因此，我总结的方法如下：

#region C# 字节转Int

        public static int GetValue(byte by)
        {
            return Convert.ToInt32(by);
        }

        #region 16进制转十进制 高字节在前
        /// <summary>
        /// 16进制转十进制 高字节在前
        /// </summary>
        /// <param name="Ary"></param>
        /// <returns></returns>
        public static int GetValue(List<byte> Ary)
        {
            double result = 0;
            var cm = 0;
            cm = Ary.Count;
            foreach (var item in Ary)
            {
                if (cm - 1 == 0)
                {
                    result += item;
                }
                else
                {
                    result += item * Math.Pow(16, (cm * 2 - 2));
                    cm--;
                }

            }
            return Convert.ToInt32(result);
        }
        /// <summary>
        /// 高字节在前
        /// </summary>
        /// <param name="Ary"></param>
        /// <returns></returns>
        public static int GetValue(IEnumerable<byte> Ary)
        {
            double result = 0;
            var cm = 0;
            cm = Ary.Count();
            foreach (var item in Ary)
            {
                if (cm - 1 == 0)
                {
                    result += item;
                }
                else
                {
                    result += item * Math.Pow(16, (cm * 2 - 2));
                    cm--;
                }

            }
            return Convert.ToInt32(result);
        }
        /// <summary>
        /// 16进制转十进制 具体参考十六进制的数值
        /// </summary>
        /// <param name="Ary"></param>
        /// <returns></returns>
        public static int GetValue(List<int> Ary)
        {
            double result = 0;
            var cm = 0;
            cm = Ary.Count;
            foreach (var item in Ary)
            {
                if (cm - 1 == 0)
                {
                    result += item;
                }
                else
                {
                    result += item * Math.Pow(16, (cm * 2 - 2));
                    cm--;
                }

            }
            return Convert.ToInt32(result);
        }
        /// <summary>
        /// 16进制转十进制
        /// </summary>
        /// <param name="Ary"></param>
        /// <returns></returns>
        public static int GetValue(IEnumerable<int> Ary)
        {
            double result = 0;
            var cm = 0;
            cm = Ary.Count();
            foreach (var item in Ary)
            {
                if (cm - 1 == 0)
                {
                    result += item;
                }
                else
                {
                    result += item * Math.Pow(16, (cm * 2 - 2));
                    cm--;
                }

            }
            return Convert.ToInt32(result);
        }
        #endregion

        #region 16进制转十进制 低字节在前
        /// <summary>
        /// 16进制转十进制 高字节在前
        /// </summary>
        /// <param name="Ary"></param>
        /// <returns></returns>
        public static int GetValueLH(List<byte> Ary)
        {
            Ary.Reverse();
            double result = 0;
            var cm = 0;
            cm = Ary.Count;
            foreach (var item in Ary)
            {
                if (cm - 1 == 0)
                {
                    result += item;
                }
                else
                {
                    result += item * Math.Pow(16, (cm * 2 - 2));
                    cm--;
                }

            }
            return Convert.ToInt32(result);
        }
        /// <summary>
        /// 低字节在前
        /// </summary>
        /// <param name="Ary"></param>
        /// <returns></returns>
        public static int GetValueLH(IEnumerable<byte> Ary)
        {
            Ary.Reverse();
            double result = 0;
            var cm = 0;
            cm = Ary.Count();
            foreach (var item in Ary)
            {
                if (cm - 1 == 0)
                {
                    result += item;
                }
                else
                {
                    result += item * Math.Pow(16, (cm * 2 - 2));
                    cm--;
                }

            }
            return Convert.ToInt32(result);
        }
        /// <summary>
        /// 16进制转十进制 低字节在前
        /// </summary>
        /// <param name="Ary"></param>
        /// <returns></returns>
        public static int GetValueLH(List<int> Ary)
        {
            Ary.Reverse();
            double result = 0;
            var cm = 0;
            cm = Ary.Count;
            foreach (var item in Ary)
            {
                if (cm - 1 == 0)
                {
                    result += item;
                }
                else
                {
                    result += item * Math.Pow(16, (cm * 2 - 2));
                    cm--;
                }

            }
            return Convert.ToInt32(result);
        }
        /// <summary>
        /// 16进制转十进制 低字节在前
        /// </summary>
        /// <param name="Ary"></param>
        /// <returns></returns>
        public static int GetValueLH(IEnumerable<int> Ary)
        {
            Ary.Reverse();
            double result = 0;
            var cm = 0;
            cm = Ary.Count();
            foreach (var item in Ary)
            {
                if (cm - 1 == 0)
                {
                    result += item;
                }
                else
                {
                    result += item * Math.Pow(16, (cm * 2 - 2));
                    cm--;
                }

            }
            return Convert.ToInt32(result);
        }
        #endregion

        #endregion

 

扩展：int数值转字节：

 

var by4 = BitConverter.GetBytes(8888);//长度四字节
var by2 = BitConverter.GetBytes(Convert.ToUInt16(8888));//长度两字节

C# base64 转 byte[]

        static void Main(string[] args)
        {
            string btinfo = @"MDAwMDAwMDAwMDAwMDAwMAHgAMgB7wAATjcBAXEBqAADAGEM7QzoR0UPDOkM6wzrDOkM6QzsDOwM7QzrDOgM6gzpDOoM6QzpAkdFAAAAAAANAQEBAQEBAAAAAAAAAAAAAAA=";
            var Bys = Encoding.Default.GetBytes(btinfo);
            var Bse64Bys = Convert.FromBase64String(btinfo);
            Console.WriteLine("普通byte数组，8位表示一个普通字符，长度为："+Bys.Length);
            Console.WriteLine("Base64byte数组，6位表示一个base64字符，长度为：" + Bse64Bys.Length);
            Console.ReadLine();
        }

继续转发别人的一篇【2020-12-24】

C#中的Byte，String，Int，Hex之间的转换函数

 转化字符串：aabb00000000001a160100000008313233343536373839303131323233330100ffff9775 为字节数组

整理转换方法：

 public class BytesTranfer
    {
        /// <summary> Convert a string of hex digits (ex: E4 CA B2) to a byte array. </summary>
        /// <param name="s"> The string containing the hex digits (with or without spaces). </param>
        /// <returns> Returns an array of bytes. </returns>
        public byte[] HexStringToByteArray(string s)
        {
            s = s.Replace(" ", "");
            byte[] buffer = new byte[s.Length / 2];
            for (int i = 0; i < s.Length; i += 2)
            {
                buffer[i / 2] = (byte)Convert.ToByte(s.Substring(i, 2), 16);
            }

            return buffer;
        }

        /// <summary> Converts an array of bytes into a formatted string of hex digits (ex: E4 CA B2)</summary>
        /// <param name="data"> The array of bytes to be translated into a string of hex digits. </param>
        /// <returns> Returns a well formatted string of hex digits with spacing. </returns>
        public string ByteArrayToHexString(byte[] data)
        {
            StringBuilder sb = new StringBuilder(data.Length * 3);
            foreach (byte b in data)
            {
                sb.Append(Convert.ToString(b, 16).PadLeft(2, '0').PadRight(3, ' '));
            }

            return sb.ToString().ToUpper();
        }

        /// <summary>
        /// 将一条十六进制字符串转换为ASCII
        /// </summary>
        /// <param name="hexstring">一条十六进制字符串</param>
        /// <returns>返回一条ASCII码</returns>
        public static string HexStringToASCII(string hexstring)
        {
            byte[] bt = HexStringToBinary(hexstring);
            string lin = "";
            for (int i = 0; i < bt.Length; i++)
            {
                lin = lin + bt[i] + " ";
            }


            string[] ss = lin.Trim().Split(new char[] { ' ' });
            char[] c = new char[ss.Length];
            int a;
            for (int i = 0; i < c.Length; i++)
            {
                a = Convert.ToInt32(ss[i]);
                c[i] = Convert.ToChar(a);
            }

            string b = new string(c);
            return b;
        }


        /**/
        /// <summary>
        /// 16进制字符串转换为二进制数组
        /// </summary>
        /// <param name="hexstring">用空格切割字符串</param>
        /// <returns>返回一个二进制字符串</returns>
        public static byte[] HexStringToBinary(string hexstring)
        {

            string[] tmpary = hexstring.Trim().Split(' ');
            byte[] buff = new byte[tmpary.Length];
            for (int i = 0; i < buff.Length; i++)
            {
                buff[i] = Convert.ToByte(tmpary[i], 16);
            }
            return buff;
        }


        /// <summary>
        /// 将byte型转换为字符串
        /// </summary>
        /// <param name="arrInput">byte型数组</param>
        /// <returns>目标字符串</returns>
        private string ByteArrayToString(byte[] arrInput)
        {
            int i;
            StringBuilder sOutput = new StringBuilder(arrInput.Length);
            for (i = 0; i < arrInput.Length; i++)
            {
                sOutput.Append(arrInput[i].ToString("X2"));
            }
            //将此实例的值转换为System.String
            return sOutput.ToString();
        }



        /// <summary>
        /// 对接收到的数据进行解包（将接收到的byte型数组解包为Unicode字符串）
        /// </summary>
        /// <param name="recbytes">byte型数组</param>
        /// <returns>Unicode编码的字符串</returns>
        public string disPackage(byte[] recbytes)
        {
            string temp = "";
            foreach (byte b in recbytes)
                temp += b.ToString("X2") + " ";//ToString("X2") 为C#中的字符串格式控制符
            return temp;
        }

        /**
    * int转byte[]
    * 该方法将一个int类型的数据转换为byte[]形式，因为int为32bit，而byte为8bit所以在进行类型转换时，知会获取低8位，
    * 丢弃高24位。通过位移的方式，将32bit的数据转换成4个8bit的数据。注意 &0xff，在这当中，&0xff简单理解为一把剪刀，
    * 将想要获取的8位数据截取出来。
    * @param i 一个int数字
    * @return byte[]
    */
        public static byte[] int2ByteArray(int i)
        {
            byte[] result = new byte[4];
            result[0] = (byte)((i >> 24) & 0xFF);
            result[1] = (byte)((i >> 16) & 0xFF);
            result[2] = (byte)((i >> 8) & 0xFF);
            result[3] = (byte)(i & 0xFF);
            return result;
        }
        /**
         * byte[]转int
         * 利用int2ByteArray方法，将一个int转为byte[]，但在解析时，需要将数据还原。同样使用移位的方式，将适当的位数进行还原，
         * 0xFF为16进制的数据，所以在其后每加上一位，就相当于二进制加上4位。同时，使用|=号拼接数据，将其还原成最终的int数据
         * @param bytes byte类型数组
         * @return int数字
         */
        public static int bytes2Int(byte[] bytes)
        {
            int num = bytes[3] & 0xFF;
            num |= ((bytes[2] << 8) & 0xFF00);
            num |= ((bytes[1] << 16) & 0xFF0000);
            num |= ((bytes[0] << 24) & 0xFF0000);
            return num;
        }

        public static string Int2String(int str)
        {
            string S = Convert.ToString(str);
            return S;
        }

        public static int String2Int(string str)
        {
            int a;
            int.TryParse(str, out a);
            int a1 = Convert.ToInt32(str);
            return a1;
        }


        /*将int转为低字节在后，高字节在前的byte数组
b[0] = 11111111(0xff) & 01100001
b[1] = 11111111(0xff) & 00000000
b[2] = 11111111(0xff) & 00000000
b[3] = 11111111(0xff) & 00000000
*/
        public byte[] IntToByteArray2(int value)
        {
            byte[] src = new byte[4];
            src[0] = (byte)((value >> 24) & 0xFF);
            src[1] = (byte)((value >> 16) & 0xFF);
            src[2] = (byte)((value >> 8) & 0xFF);
            src[3] = (byte)(value & 0xFF);
            return src;
        }
        //将高字节在前转为int，低字节在后的byte数组(与IntToByteArray2想对应)
        public int ByteArrayToInt2(byte[] bArr)
        {
            if (bArr.Length != 4)
            {
                return -1;
            }
            return (int)((((bArr[0] & 0xff) << 24)
                       | ((bArr[1] & 0xff) << 16)
                       | ((bArr[2] & 0xff) << 8)
   | ((bArr[3] & 0xff) << 0)));
        }

        public static string StringToHexArray(string input)
        {
            char[] values = input.ToCharArray();
            StringBuilder sb = new StringBuilder(input.Length * 3);
            foreach (char letter in values)
            {
                // Get the integral value of the character.
                int value = Convert.ToInt32(letter);
                // Convert the decimal value to a hexadecimal value in string form.
                string hexOutput = String.Format("{0:X}", value);
                sb.Append(Convert.ToString(value, 16).PadLeft(2, '0').PadRight(3, ' '));
            }

            return sb.ToString().ToUpper();



        }
    }

附上查找资料过程中有用的一些资料地址：

https://www.cnblogs.com/ThreeS/articles/9377547.html

https://www.cnblogs.com/screes/p/5633383.html

还有一个关于补零的：https://blog.csdn.net/qq_22889875/article/details/79320678

 

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