问题
I have a string with 14 characters . This is a hex represantation of 7bytes. I want to convert it to binary. I tried using Convert.ToString(Convert.ToInt32(hexstring, 16), 2); For small strings this works but for 14 characters it will not work because the result is too large.
How can i manage this? Keep in mind that the output of the conversion should be a binary string with a lengeth of 56 characters (we must keep the leading zeros). (e.g. conversion of (byte)0x01 should yield "00000001" rather than "1")
回答1:
You can just convert each hexadecimal digit into four binary digits:
string binarystring = String.Join(String.Empty,
hexstring.Select(
c => Convert.ToString(Convert.ToInt32(c.ToString(), 16), 2).PadLeft(4, '0')
)
);
You need a using System.Linq; a the top of the file for this to work.
回答2:
Convert.ToString(Convert.ToInt64(hexstring, 16), 2);Maybe? Or
Convert.ToString(Convert.ToInt64(hexstring, 16), 2).PadLeft(56, '0');回答3:
Why not just take the simple approach and define your own mapping?
private static readonly Dictionary<char, string> hexCharacterToBinary = new Dictionary<char, string> {
{ '0', "0000" },
{ '1', "0001" },
{ '2', "0010" },
{ '3', "0011" },
{ '4', "0100" },
{ '5', "0101" },
{ '6', "0110" },
{ '7', "0111" },
{ '8', "1000" },
{ '9', "1001" },
{ 'a', "1010" },
{ 'b', "1011" },
{ 'c', "1100" },
{ 'd', "1101" },
{ 'e', "1110" },
{ 'f', "1111" }
};
public string HexStringToBinary(string hex) {
StringBuilder result = new StringBuilder();
foreach (char c in hex) {
// This will crash for non-hex characters. You might want to handle that differently.
result.Append(hexCharacterToBinary[char.ToLower(c)]);
}
return result.ToString();
}
Note that this will keep leading zeros. So "aa" would be converted to "10101010" while "00000aa" would be converted to "0000000000000000000010101010".
回答4:
You can get a byte array from hex string using this code
public static byte[] StringToByteArray(String hex)
{
int NumberChars = hex.Length;
byte[] bytes = new byte[NumberChars / 2];
for (int i = 0; i < NumberChars; i += 2)
bytes[i / 2] = Convert.ToByte(hex.Substring(i, 2), 16);
return bytes;
}
回答5:
My C++ background answer:
private Byte[] HexToBin(string pHexString)
{
if (String.IsNullOrEmpty(pHexString))
return new Byte[0];
if (pHexString.Length % 2 != 0)
throw new Exception("Hexstring must have an even length");
Byte[] bin = new Byte[pHexString.Length / 2];
int o = 0;
int i = 0;
for (; i < pHexString.Length; i += 2, o++)
{
switch (pHexString[i])
{
case '0': bin[o] = 0x00; break;
case '1': bin[o] = 0x10; break;
case '2': bin[o] = 0x20; break;
case '3': bin[o] = 0x30; break;
case '4': bin[o] = 0x40; break;
case '5': bin[o] = 0x50; break;
case '6': bin[o] = 0x60; break;
case '7': bin[o] = 0x70; break;
case '8': bin[o] = 0x80; break;
case '9': bin[o] = 0x90; break;
case 'A':
case 'a': bin[o] = 0xa0; break;
case 'B':
case 'b': bin[o] = 0xb0; break;
case 'C':
case 'c': bin[o] = 0xc0; break;
case 'D':
case 'd': bin[o] = 0xd0; break;
case 'E':
case 'e': bin[o] = 0xe0; break;
case 'F':
case 'f': bin[o] = 0xf0; break;
default: throw new Exception("Invalid character found during hex decode");
}
switch (pHexString[i+1])
{
case '0': bin[o] |= 0x00; break;
case '1': bin[o] |= 0x01; break;
case '2': bin[o] |= 0x02; break;
case '3': bin[o] |= 0x03; break;
case '4': bin[o] |= 0x04; break;
case '5': bin[o] |= 0x05; break;
case '6': bin[o] |= 0x06; break;
case '7': bin[o] |= 0x07; break;
case '8': bin[o] |= 0x08; break;
case '9': bin[o] |= 0x09; break;
case 'A':
case 'a': bin[o] |= 0x0a; break;
case 'B':
case 'b': bin[o] |= 0x0b; break;
case 'C':
case 'c': bin[o] |= 0x0c; break;
case 'D':
case 'd': bin[o] |= 0x0d; break;
case 'E':
case 'e': bin[o] |= 0x0e; break;
case 'F':
case 'f': bin[o] |= 0x0f; break;
default: throw new Exception("Invalid character found during hex decode");
}
}
return bin;
}
回答6:
What if you convert one character at a time? I'm can't test this out, but the idea should work.
//Convert.ToString(Convert.ToInt32(hexstring, 16), 2)
StringBuilder sb = new StringBuilder();
foreach( char c in hexstring.ToCharArray() ){
sb.Append( Convert.ToString(Convert.ToInt32(c.ToString(), 16), 2);
}
回答7:
You can do this.
I have put it in a class called UtilMath this is a good Idea as, if you ever use it in a different program you can use the class again. And as the name implies this is for all my Math functions.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Math.Util
{
class UtilMath
{
public static string hex2binary(string hexvalue)
{
// Convert.ToUInt32 this is an unsigned int
// so no negative numbers but it gives you one more bit
// it much of a muchness
// Uint MAX is 4,294,967,295 and MIN is 0
// this padds to 4 bits so 0x5 = "0101"
return String.Join(String.Empty, hexvalue.Select(c => Convert.ToString(Convert.ToUInt32(c.ToString(), 16), 2).PadLeft(4, '0')));
}
}
}
now before you use it you need to include it,
using Math.Util
then if you need to use it you can call it by going
UtilMath.hex2binary("FF");
Or
String hexString = "FF";
UtilMath.hex2binary(hexString);
Hope this helps.
来源：https://stackoverflow.com/questions/6617284/c-sharp-how-convert-large-hex-string-to-binary