using System;

using System.Collections.Generic;

using System.IO;

​

Dictionary<byte, string> vals = new() {

    [1] = "a",

    [5] = "s",

    [9] = "bxz",

    [42] = "aaaaaaaa"

};

​

// Encode

byte[] bytes;

using (MemoryStream ms = new())

{

    using BinaryWriter bw = new(ms);

    bw.Write(vals.Count);

    foreach (KeyValuePair<byte, string> kvp in vals)

    {

        bw.Write(kvp.Key);

        bw.Write(kvp.Value);

    }

    bytes = ms.ToArray();

}

​

// Display

FiddleHelper.Dump(Convert.ToHexString(bytes));

​

// Decode

using (MemoryStream ms = new(bytes))

{

    using BinaryReader br = new(ms);

    int itemCount = br.ReadInt32();

    Dictionary<byte, string> decoded = new(itemCount);

    for (int i = 0; i < itemCount; i++)

    {

        byte key = br.ReadByte();

        string value = br.ReadString();

        decoded.Add(key, value);

    }

    FiddleHelper.Dump(decoded);

}