C# 字符转换方法集合

为了以后项目方便，收集一下字符转换的方法，可能有点乱，慢慢找。

1.负（有符号）数和16进制转换

转载于:https://www.cnblogs.com/zhangpengshou/archive/2011/12/17/2291418.html

思路：

①负数转换为正数；例：-5，先转换成5（0000 0101）;第一位标识正负

②先将十进制转换为二进制通过；例：将5转换为二进制，得到结果0000 0101

③求反码；例：将上面例子求反码，得到结果：1111 1010（即0变成1,1变0）

④求补码；例：将第四步结果求补码，得到结果：1111 1011（最后一位加1）

⑤转十六进制；1111 1011转十六进制即得：FB

1.1 负（有符号）数转为16进制（字符串）

///   <summary> 
///  负数转十六进制
///   </summary> 
///   <param name="iNumber"></param> 
///   <returns></returns> 
private  string NegativeToHexString( int iNumber) 
{ 
     string strResult =  string.Empty; 

     if (iNumber <  0) 
    { 
        iNumber = -iNumber; 

         string strNegate =  string.Empty; 

         char[] binChar = Convert.ToString(iNumber,  2).PadLeft( 8,  ' 0 ').ToArray(); 

         foreach ( char ch  in binChar) 
        { 
             if (Convert.ToInt32(ch) ==  48) 
            { 
                strNegate +=  " 1 "; 
            } 
             else 
            { 
                strNegate +=  " 0 "; 
            } 
        } 

         int iComplement = Convert.ToInt32(strNegate, 2) +  1; 

        strResult = Convert.ToString(iComplement,  16).ToUpper(); 
    } 

     return strResult; 
}

1.2 16进制（字符串）转为（有符号）数

/// <summary> 
/// 十六进制转为负数
///</summary>

///<param name="strNumber"></param>

///<returns></returns>

private int HexStringToNegative(string strNumber)
{
    int iNegate = 0;
    int iNumber = Convert.ToInt32(strNumber, 16);

    if (iNumber > 127)
    {
        int iComplement = iNumber - 1;
        string strNegate = string.Empty;

        char[] binChar = Convert.ToString(iComplement, 2).PadLeft(8, '0').ToArray();

        foreach (char ch in binChar)
        {
            if (Convert.ToInt32(ch) == 48)
            {
                strNegate += "1";
            }
            else
            {
                strNegate += "0";
            }
        }

        iNegate = - Convert.ToInt32(strNegate, 2);
    }

    return iNegate;
}

2 两个字节（高低位）转化为有符号整数

        private int Byte2ToNegative(byte b1, byte b2)  //2字节转整数(有符号)
        {
            int iNegate = 0;
            int iNumber = b1 * 256 + b2;

            if (iNumber > 32767)
            {
                int iComplement = iNumber - 1;
                string strNegate = string.Empty;

                char[] binChar = Convert.ToString(iComplement, 2).PadLeft(8, '0').ToArray();

                foreach (char ch in binChar)
                {
                    if (Convert.ToInt32(ch) == 48)
                    {
                        strNegate += "1";
                    }
                    else
                    {
                        strNegate += "0";
                    }
                }
                iNegate = -Convert.ToInt32(strNegate, 2);
            }
            else
            {
                iNegate = iNumber;
            }
            return iNegate;
        }

3 ModBus报文拼接

3.1 发送报文拼接

        private List<byte> MessageComb(byte SlaveId, byte fcnCode, ushort Address, ushort data)//
        {
            //拼接报文
            List<byte> SendCommand = new List<byte>();
            //从站地址+功能码+起始高位+起始低位+数量高位+数量地位+CRC校验位
            SendCommand.Add(SlaveId); //加单数
            SendCommand.Add(fcnCode); //读取
            SendCommand.Add((byte)(Address / 256));  //高位
            SendCommand.Add((byte)(Address % 256));  //低位
            SendCommand.Add((byte)(data / 256));  //高位
            SendCommand.Add((byte)(data % 256));  //低位
            byte[] crc = Crc16(SendCommand.ToArray(), 6);  //校验
            SendCommand.AddRange(crc); //   CRC
                                       //发送报文
            return SendCommand;
        }
        /// <summary>
        /// CRC效验
        /// </summary>
        /// <param name="pucFrame">效验数据</param>
        /// <param name="usLen">数据长度</param>
        /// <returns>效验结果</returns>
        private byte[] Crc_16(byte[] pucFrame, int usLen)   //校验方法 返回2个字节
        {
            int i = 0;
            byte[] res = new byte[2] { 0xFF, 0xFF };

            UInt16 iIndex = 0x0000;

            while (usLen-- > 0)
            {
                iIndex = (UInt16)(res[0] ^ pucFrame[i++]);
                res[0] = (byte)(res[1] ^ aucCRCHi[iIndex]);
                res[1] = aucCRCLO[iIndex];
            }
            return res;
        }
        private static readonly byte[] aucCRCLO = {
            0x00, 0xC0, 0xC1, 0x01, 0xC3, 0x03, 0x02, 0xC2, 0xC6, 0x06, 0x07, 0xC7,
            0x05, 0xC5, 0xC4, 0x04, 0xCC, 0x0C, 0x0D, 0xCD, 0x0F, 0xCF, 0xCE, 0x0E,
           0x0A, 0xCA, 0xCB, 0x0B, 0xC9, 0x09, 0x08, 0xC8, 0xD8, 0x18, 0x19, 0xD9,
            0x1B, 0xDB, 0xDA, 0x1A, 0x1E, 0xDE, 0xDF, 0x1F, 0xDD, 0x1D, 0x1C, 0xDC,
            0x14, 0xD4, 0xD5, 0x15, 0xD7, 0x17, 0x16, 0xD6, 0xD2, 0x12, 0x13, 0xD3,
            0x11, 0xD1, 0xD0, 0x10, 0xF0, 0x30, 0x31, 0xF1, 0x33, 0xF3, 0xF2, 0x32,
          0x36, 0xF6, 0xF7, 0x37, 0xF5, 0x35, 0x34, 0xF4, 0x3C, 0xFC, 0xFD, 0x3D,
           0xFF, 0x3F, 0x3E, 0xFE, 0xFA, 0x3A, 0x3B, 0xFB, 0x39, 0xF9, 0xF8, 0x38,
            0x28, 0xE8, 0xE9, 0x29, 0xEB, 0x2B, 0x2A, 0xEA, 0xEE, 0x2E, 0x2F, 0xEF,
            0x2D, 0xED, 0xEC, 0x2C, 0xE4, 0x24, 0x25, 0xE5, 0x27, 0xE7, 0xE6, 0x26,
             0x22, 0xE2, 0xE3, 0x23, 0xE1, 0x21, 0x20, 0xE0, 0xA0, 0x60, 0x61, 0xA1,
           0x63, 0xA3, 0xA2, 0x62, 0x66, 0xA6, 0xA7, 0x67, 0xA5, 0x65, 0x64, 0xA4,
            0x6C, 0xAC, 0xAD, 0x6D, 0xAF, 0x6F, 0x6E, 0xAE, 0xAA, 0x6A, 0x6B, 0xAB,
            0x69, 0xA9, 0xA8, 0x68, 0x78, 0xB8, 0xB9, 0x79, 0xBB, 0x7B, 0x7A, 0xBA,
            0xBE, 0x7E, 0x7F, 0xBF, 0x7D, 0xBD, 0xBC, 0x7C, 0xB4, 0x74, 0x75, 0xB5,
            0x77, 0xB7, 0xB6, 0x76, 0x72, 0xB2, 0xB3, 0x73, 0xB1, 0x71, 0x70, 0xB0,
           0x50, 0x90, 0x91, 0x51, 0x93, 0x53, 0x52, 0x92, 0x96, 0x56, 0x57, 0x97,
           0x55, 0x95, 0x94, 0x54, 0x9C, 0x5C, 0x5D, 0x9D, 0x5F, 0x9F, 0x9E, 0x5E,
          0x5A, 0x9A, 0x9B, 0x5B, 0x99, 0x59, 0x58, 0x98, 0x88, 0x48, 0x49, 0x89,
            0x4B, 0x8B, 0x8A, 0x4A, 0x4E, 0x8E, 0x8F, 0x4F, 0x8D, 0x4D, 0x4C, 0x8C,
            0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42, 0x43, 0x83,
            0x41, 0x81, 0x80, 0x40
        };