//1.请问c#中如何将十进制数的字符串转化成十六进制数的字符串
 
//十进制转二进制
Console.WriteLine("十进制166的二进制表示: "+Convert.ToString(166, 2));
//十进制转八进制
Console.WriteLine("十进制166的八进制表示: "+Convert.ToString(166, 8));
//十进制转十六进制
Console.WriteLine("十进制166的十六进制表示: "+Convert.ToString(166, 16));
    
//二进制转十进制
Console.WriteLine("二进制 111101 的十进制表示: "+Convert.ToInt32("111101", 2));
//八进制转十进制
Console.WriteLine("八进制 44 的十进制表示: "+Convert.ToInt32("44", 8));
//十六进制转十进制
Console.WriteLine("十六进制 CC的十进制表示: "+Convert.ToInt32("CC", 16));
 


//2.在串口通讯过程中，经常要用到 16进制与字符串、字节数组之间的转换
private string StringToHexString(string s,Encoding encode)
{
    byte[] b = encode.GetBytes(s);//按照指定编码将string编程字节数组
    string result = string.Empty;
    for (int i = 0; i < b.Length; i++)//逐字节变为16进制字符，以%隔开
    {
        result += "%"+Convert.ToString(b[i], 16);
    }
    return result;
}
private string HexStringToString(string hs, Encoding encode)
{
    //以%分割字符串，并去掉空字符
    string[] chars = hs.Split(new char[]{'%'},StringSplitOptions.RemoveEmptyEntries);
    byte[] b = new byte[chars.Length];
    //逐个字符变为16进制字节数据
    for (int i = 0; i < chars.Length; i++)
    {
        b[i] = Convert.ToByte(chars[i], 16);
    }
    //按照指定编码将字节数组变为字符串
    return encode.GetString(b);
}
 
/// <summary>
/// 字符串转16进制字节数组
/// </summary>
/// <param name="hexString"></param>
/// <returns></returns>
private static byte[] strToToHexByte(string hexString)
{
     hexString = hexString.Replace(" ", "");
   if ((hexString.Length % 2) != 0)
         hexString += " ";
    byte[] returnBytes = new byte[hexString.Length / 2];
    for (int i = 0; i < returnBytes.Length; i++)
        returnBytes[i] = Convert.ToByte(hexString.Substring(i * 2, 2), 16);
    return returnBytes;
 }
 
/// <summary>
/// 字节数组转16进制字符串
/// </summary>
/// <param name="bytes"></param>
/// <returns></returns>
public static string byteToHexStr(byte[] bytes)
{
    string returnStr = "";
    if (bytes != null)
    {
        for (int i = 0; i < bytes.Length; i++)
        {
             returnStr += bytes[i].ToString("X2");
         }
     }
    return returnStr;
 }
 
/// <summary>
/// 从汉字转换到16进制
/// </summary>
/// <param name="s"></param>
/// <param name="charset">编码,如"utf-8","gb2312"</param>
/// <param name="fenge">是否每字符用逗号分隔</param>
/// <returns></returns>
public static string ToHex(string s, string charset, bool fenge)
{
    if ((s.Length % 2) != 0)
    {
         s += " ";//空格
        //throw new ArgumentException("s is not valid chinese string!");
     }
     System.Text.Encoding chs = System.Text.Encoding.GetEncoding(charset);
    byte[] bytes = chs.GetBytes(s);
    string str = "";
    for (int i = 0; i < bytes.Length; i++)
    {
        str += string.Format("{0:X}", bytes[i]);
        if (fenge && (i != bytes.Length - 1))
        {
             str += string.Format("{0}", ",");
         }
     }
    return str.ToLower();
 }
 
 
///<summary>
/// 从16进制转换成汉字
/// </summary>
/// <param name="hex"></param>
/// <param name="charset">编码,如"utf-8","gb2312"</param>
/// <returns></returns>
public static string UnHex(string hex, string charset)
{
   if (hex == null)
        throw new ArgumentNullException("hex");
     hex = hex.Replace(",", "");
     hex = hex.Replace("\n", "");
     hex = hex.Replace("\\", "");
     hex = hex.Replace(" ", "");
    if (hex.Length % 2 != 0)
    {
         hex += "20";//空格
     }
    // 需要将 hex 转换成 byte 数组。 
    byte[] bytes = new byte[hex.Length / 2];
 
   for (int i = 0; i < bytes.Length; i++)
    {
        try
        {
            // 每两个字符是一个 byte。 
             bytes[i] = byte.Parse(hex.Substring(i * 2, 2),
             System.Globalization.NumberStyles.HexNumber);
         }
        catch
        {
            // Rethrow an exception with custom message. 
            throw new ArgumentException("hex is not a valid hex number!", "hex");
         }
     }
     System.Text.Encoding chs = System.Text.Encoding.GetEncoding(charset);
    return chs.GetString(bytes);
 }

本文引自：https://blog.csdn.net/smartsmile2012/article/details/70908541