如何将十六进制字符串转换为字节数组?(复制)

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How do you convert a byte array to a hexadecimal string, and vice versa? 38 answers
如何将一个字节数组转换成十六进制字符串，反之亦然?38个答案

Can we convert a hex string to a byte array using a built-in function in C# or do I have to make a custom method for this?

我们可以使用c#内的内置函数将十六进制字符串转换成字节数组吗?或者我需要为此定制一个方法吗?

4 个解决方案

#1

388

Here's a nice fun LINQ example.

这是一个很有趣的LINQ例子。

public static byte[] StringToByteArray(string hex) {
    return Enumerable.Range(0, hex.Length)
                     .Where(x => x % 2 == 0)
                     .Select(x => Convert.ToByte(hex.Substring(x, 2), 16))
                     .ToArray();
}

#2

I did some research and found out that byte.Parse is even slower than Convert.ToByte. The fastest conversion I could come up with uses approximately 15 ticks per byte.

我做了一些研究，发现了那个字节。解析甚至比Convert.ToByte更慢。我能想到的最快的转换是每字节约15个节拍。

    public static byte[] StringToByteArrayFastest(string hex) {
        if (hex.Length % 2 == 1)
            throw new Exception("The binary key cannot have an odd number of digits");

        byte[] arr = new byte[hex.Length >> 1];

        for (int i = 0; i < hex.Length >> 1; ++i)
        {
            arr[i] = (byte)((GetHexVal(hex[i << 1]) << 4) + (GetHexVal(hex[(i << 1) + 1])));
        }

        return arr;
    }

    public static int GetHexVal(char hex) {
        int val = (int)hex;
        //For uppercase A-F letters:
        return val - (val < 58 ? 48 : 55);
        //For lowercase a-f letters:
        //return val - (val < 58 ? 48 : 87);
        //Or the two combined, but a bit slower:
        //return val - (val < 58 ? 48 : (val < 97 ? 55 : 87));
    }

// also works on .NET Micro Framework where (in SDK4.3) byte.Parse(string) only permits integer formats.

//也适用于。net微框架(在SDK4.3中)byte.Parse(string)只允许整数格式。

#3

public static byte[] ConvertHexStringToByteArray(string hexString)
{
    if (hexString.Length % 2 != 0)
    {
        throw new ArgumentException(String.Format(CultureInfo.InvariantCulture, "The binary key cannot have an odd number of digits: {0}", hexString));
    }

    byte[] HexAsBytes = new byte[hexString.Length / 2];
    for (int index = 0; index < HexAsBytes.Length; index++)
    {
        string byteValue = hexString.Substring(index * 2, 2);
        HexAsBytes[index] = byte.Parse(byteValue, NumberStyles.HexNumber, CultureInfo.InvariantCulture);
    }

    return HexAsBytes; 
}

#4

I think this may work.

我认为这行得通。

public static byte[] StrToByteArray(string str)
    {
        Dictionary<string, byte> hexindex = new Dictionary<string, byte>();
        for (int i = 0; i <= 255; i++)
            hexindex.Add(i.ToString("X2"), (byte)i);

        List<byte> hexres = new List<byte>();
        for (int i = 0; i < str.Length; i += 2)            
            hexres.Add(hexindex[str.Substring(i, 2)]);

        return hexres.ToArray();
    }

#1

388