Decode hexadecimal bytes.

C#: FromHexString and ToHexString handle binary data without manually parsing pairs of characters.

using System;
using System.IO;
using System.Linq;
using System.Text;
using System.Text.Json;
using System.Text.RegularExpressions;
using System.Collections.Generic;
using System.Globalization;
using System.Security.Cryptography;
using System.Threading;
using System.Threading.Tasks;

byte[] bytes = Convert.FromHexString("4869");
Console.WriteLine(Encoding.ASCII.GetString(bytes));
Console.WriteLine(Convert.ToHexString(bytes));

Expected output EXAMPLE

Hi
4869

Details

Use Program.cs in a .NET 8 console project and run dotnet run. Uses only the .NET standard libraries. FromHexString and ToHexString handle binary data without manually parsing pairs of characters.

✓ Verified

Tested on Ubuntu 24.04.5 LTS · 2026-11-02 18:07:04 UTC · 8.0.425 · libc6 2.39-0ubuntu8.9

Test inputs, results and environment

The exact published code ran in a dedicated Linux test container with prepared inputs. Unprivileged snippet process, external networking disabled, read-only root filesystem, and a fresh temporary working directory. Fixtures and output records are isolated from the application database. Testing covers this example and its stated checks, not every input, operating system, or runtime version. The Linux container shares its host's kernel; this is not a native Windows test.

Architecture / host kernel: x86_64 / 6.18.54.1-microsoft-standard-WSL2
Snippet identity / locale: uid=65534, gid=65534 (unprivileged) / C.UTF-8
Interpreter invocation: dotnet build --no-restore && dotnet out/csharp.dll
Container image ID: sha256:32dc2d998158b6554c99b73b533f423696a0f3e31e8cbea9db10b5eee9a2fadd
Code SHA-256: 14a394dbf2b68024aa644afd98dd7905cbbca2f7562988944b1cbf9ecceb0a87
Dependencies: libc6 2.39-0ubuntu8.9

Test input setup

These are the prepared inputs used by the test harness. See Details above for the prerequisites and how to run this example.

# No input files required.

Observed standard output

Hi
4869

Exit code: 0. Standard error: empty. Validation: Exact stdout comparison. System-dependent values above are one recorded run.