In .NET 5.0 and later you can use the Convert.ToHexString()
method.
using System;
using System.Text;
string value = "Hello world";
byte[] bytes = Encoding.UTF8.GetBytes(value);
string hexString = Convert.ToHexString(bytes);
Console.WriteLine($"String value: \"{value}\"");
Console.WriteLine($" Hex value: \"{hexString}\"");
Running the above example code, you would get the following output:
String value: "Hello world"
Hex value: "48656C6C6F20776F726C64"
var result = string.Join("", input.Select(c => ((int)c).ToString("X2")));
OR
var result =string.Join("",
input.Select(c=> String.Format("{0:X2}", Convert.ToInt32(c))));
few Unicode alternatives
var s = "0";
var s1 = string.Concat(s.Select(c => $"{(int)c:x4}")); // left padded with 0 - "0030d835dfcfd835dfdad835dfe5d835dff0d835dffb"
var sL = BitConverter.ToString(Encoding.Unicode.GetBytes(s)).Replace("-", ""); // Little Endian "300035D8CFDF35D8DADF35D8E5DF35D8F0DF35D8FBDF"
var sB = BitConverter.ToString(Encoding.BigEndianUnicode.GetBytes(s)).Replace("-", ""); // Big Endian "0030D835DFCFD835DFDAD835DFE5D835DFF0D835DFFB"
// no encodding "300035D8CFDF35D8DADF35D8E5DF35D8F0DF35D8FBDF"
byte[] b = new byte[s.Length * sizeof(char)];
Buffer.BlockCopy(s.ToCharArray(), 0, b, 0, b.Length);
var sb = BitConverter.ToString(b).Replace("-", "");
According to this snippet here, this approach should be good for long strings:
private string StringToHex(string hexstring)
{
StringBuilder sb = new StringBuilder();
foreach (char t in hexstring)
{
//Note: X for upper, x for lower case letters
sb.Append(Convert.ToInt32(t).ToString("x"));
}
return sb.ToString();
}
usage:
string result = StringToHex("Hello world"); //returns "48656c6c6f20776f726c64"
Another approach in one line
string input = "Hello world";
string result = String.Concat(input.Select(x => ((int)x).ToString("x")));
For Unicode support:
public class HexadecimalEncoding
{
public static string ToHexString(string str)
{
var sb = new StringBuilder();
var bytes = Encoding.Unicode.GetBytes(str);
foreach (var t in bytes)
{
sb.Append(t.ToString("X2"));
}
return sb.ToString(); // returns: "48656C6C6F20776F726C64" for "Hello world"
}
public static string FromHexString(string hexString)
{
var bytes = new byte[hexString.Length / 2];
for (var i = 0; i < bytes.Length; i++)
{
bytes[i] = Convert.ToByte(hexString.Substring(i * 2, 2), 16);
}
return Encoding.Unicode.GetString(bytes); // returns: "Hello world" for "48656C6C6F20776F726C64"
}
}
Source: Stackoverflow.com