下面是另一种方法:

public static string ByteArrayToHexString(byte[] Bytes)
{
    StringBuilder Result = new StringBuilder(Bytes.Length * 2);
    string HexAlphabet = "0123456789ABCDEF";

    foreach (byte B in Bytes)
    {
        Result.Append(HexAlphabet[(int)(B >> 4)]);
        Result.Append(HexAlphabet[(int)(B & 0xF)]);
    }

    return Result.ToString();
}

public static byte[] HexStringToByteArray(string Hex)
{
    byte[] Bytes = new byte[Hex.Length / 2];
    int[] HexValue = new int[] { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 
       0x06, 0x07, 0x08, 0x09, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
       0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F };

    for (int x = 0, i = 0; i < Hex.Length; i += 2, x += 1)
    {
        Bytes[x] = (byte)(HexValue[Char.ToUpper(Hex[i + 0]) - '0'] << 4 |
                          HexValue[Char.ToUpper(Hex[i + 1]) - '0']);
    }

    return Bytes;
}

或者，你可以像这样预先构建翻译表，以获得更快的结果:

http://blogs.msdn.com/b/blambert/archive/2009/02/22/blambert-codesnip-fast-byte-array-to-hex-string-conversion.aspx

正如其他人所说，这取决于字节数组中值的编码方式。尽管如此，您还是需要非常小心地处理这类事情，否则您可能会尝试转换未被所选编码处理的字节。

Jon Skeet有一篇关于。net中的编码和unicode的好文章。推荐阅读。

:

byte[] data = new byte[] { 0x01, 0x02, 0x03, 0x0D, 0x0E, 0x0F };
string hex = string.Empty;
data.ToList().ForEach(b => hex += b.ToString("x2"));
// use "X2" for uppercase hex letters
Console.WriteLine(hex);

结果:0102030 d0e0f

我不确定你是否需要这样做的性能，但这里是最快的方法转换字节[]到十六进制字符串，我能想到:

static readonly char[] hexchar = new char[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
public static string HexStr(byte[] data, int offset, int len, bool space = false)
{
    int i = 0, k = 2;
    if (space) k++;
    var c = new char[len * k];
    while (i < len)
    {
        byte d = data[offset + i];
        c[i * k] = hexchar[d / 0x10];
        c[i * k + 1] = hexchar[d % 0x10];
        if (space && i < len - 1) c[i * k + 2] = ' ';
        i++;
    }
    return new string(c, 0, c.Length);
}

非常快速的扩展方法(带反转):

public static class ExtensionMethods {
    public static string ToHex(this byte[] data) {
        return ToHex(data, "");
    }
    public static string ToHex(this byte[] data, string prefix) {
        char[] lookup = new char[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
        int i = 0, p = prefix.Length, l = data.Length;
        char[] c = new char[l * 2 + p];
        byte d;
        for(; i < p; ++i) c[i] = prefix[i];
        i = -1;
        --l;
        --p;
        while(i < l) {
            d = data[++i];
            c[++p] = lookup[d >> 4];
            c[++p] = lookup[d & 0xF];
        }
        return new string(c, 0, c.Length);
    }
    public static byte[] FromHex(this string str) {
        return FromHex(str, 0, 0, 0);
    }
    public static byte[] FromHex(this string str, int offset, int step) {
        return FromHex(str, offset, step, 0);
    }
    public static byte[] FromHex(this string str, int offset, int step, int tail) {
        byte[] b = new byte[(str.Length - offset - tail + step) / (2 + step)];
        byte c1, c2;
        int l = str.Length - tail;
        int s = step + 1;
        for(int y = 0, x = offset; x < l; ++y, x += s) {
            c1 = (byte)str[x];
            if(c1 > 0x60) c1 -= 0x57;
            else if(c1 > 0x40) c1 -= 0x37;
            else c1 -= 0x30;
            c2 = (byte)str[++x];
            if(c2 > 0x60) c2 -= 0x57;
            else if(c2 > 0x40) c2 -= 0x37;
            else c2 -= 0x30;
            b[y] = (byte)((c1 << 4) + c2);
        }
        return b;
    }
}

在上面的速度测试中击败所有其他人:

=== Long string test BitConvertReplace calculation Time Elapsed 2415 ms StringBuilder calculation Time Elapsed 5668 ms LinqConcat calculation Time Elapsed 11826 ms LinqJoin calculation Time Elapsed 9323 ms LinqAgg calculation Time Elapsed 7444 ms ToHexTable calculation Time Elapsed 1028 ms ToHexAcidzombie calculation Time Elapsed 1035 ms ToHexPatrick calculation Time Elapsed 814 ms ToHexKurt calculation Time Elapsed 1604 ms ByteArrayToHexString calculation Time Elapsed 1330 ms === Many string test BitConvertReplace calculation Time Elapsed 2238 ms StringBuilder calculation Time Elapsed 5393 ms LinqConcat calculation Time Elapsed 9043 ms LinqJoin calculation Time Elapsed 9131 ms LinqAgg calculation Time Elapsed 7324 ms ToHexTable calculation Time Elapsed 968 ms ToHexAcidzombie calculation Time Elapsed 969 ms ToHexPatrick calculation Time Elapsed 956 ms ToHexKurt calculation Time Elapsed 1547 ms ByteArrayToHexString calculation Time Elapsed 1277 ms

有一个内置的方法:

byte[] data = { 1, 2, 4, 8, 16, 32 };

string hex = BitConverter.ToString(data);

结果:01-02-04-08-10-20

如果你想要没有破折号，只需删除它们:

string hex = BitConverter.ToString(data).Replace("-", string.Empty);

结果:010204081020

如果你想要一个更紧凑的表示，你可以使用Base64:

string base64 = Convert.ToBase64String(data);

结果:AQIECBAg