using System;

using System.Runtime.Serialization.Formatters.Binary;

using System.Collections.Generic;

using System.IO;

​

public class Program

{

    public static void Main()

    {

        var dic = new Dictionary<string, string> { ["a"] = "b" };

​

        var bf = new BinaryFormatter();

        using (var memory = new MemoryStream())

        {

            bf.Serialize(memory, dic);

​

            memory.Seek(0, SeekOrigin.Begin);

            var dic2 = (Dictionary<string, string>)bf.Deserialize(memory);

            Console.WriteLine(dic2["a"]);

        }

    }

}