C# Hex.DecodeHex: Decode Hexadecimal Strings - Tutorial & Code Example

In C#, you can use the `System.Security.Cryptography` namespace to decode a hexadecimal encoded string.

Here's an example of how to use `Hex.DecodeHex` method in C#:

using System;
using System.Security.Cryptography;
using System.Text;

public class Program
{
    public static void Main(string[] args)
    {
        string hexString = "48656C6C6F20576F726C64"; // Hexadecimal encoded string
        
        byte[] decodedBytes = DecodeHex(hexString);
        string decodedString = Encoding.UTF8.GetString(decodedBytes);
        
        Console.WriteLine(decodedString); // Output: Hello World
    }
    
    public static byte[] DecodeHex(string hexString)
    {
        int numberChars = hexString.Length;
        byte[] bytes = new byte[numberChars / 2];

        for (int i = 0; i < numberChars; i += 2)
        {
            bytes[i / 2] = Convert.ToByte(hexString.Substring(i, 2), 16);
        }

        return bytes;
    }
}

In this example, the `DecodeHex` method takes a hexadecimal encoded string as input and converts it into a byte array. The byte array is then converted to a string using the `Encoding.UTF8.GetString` method to obtain the original decoded string.

Note: Make sure to include the `System.Security.Cryptography` and `System.Text` namespaces in your code.