C# 如何将十六进制字符串转换为字节数组？
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How can I convert a hex string to a byte array?
提问by Blankman
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# 中的内置函数将十六进制字符串转换为字节数组，还是必须为此创建自定义方法？
采纳答案by JaredPar
Here's a nice fun LINQ example.
这是一个很好玩的 LINQ 示例。
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();
}
回答by Aswath Krishnan
The following code changes the hexadecimal string to a byte array by parsing the string byte-by-byte.
以下代码通过逐字节解析字符串将十六进制字符串更改为字节数组。
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[] data = new byte[hexString.Length / 2];
for (int index = 0; index < data.Length; index++)
{
string byteValue = hexString.Substring(index * 2, 2);
data[index] = byte.Parse(byteValue, NumberStyles.HexNumber, CultureInfo.InvariantCulture);
}
return data;
}
回答by CainKellye
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 byte.Parse 比 Convert.ToByte 还要慢。我能想到的最快转换每字节使用大约 15 个滴答声。
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 Micro Framework，其中（在 SDK4.3 中）byte.Parse(string) 只允许整数格式。
回答by Rick
I think this may work.
我认为这可能奏效。
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();
}
