using System;

using System.Collections.Generic;

​

public struct User

{

    public string Name {get; set;}

    public Dictionary<string, string> Map {get; set;}

}

​

​

public class Program

{

    public static void Main()

    {

        var u = new User{ Name = "Initial User", Map = new Dictionary<string, string>() };

        u.Map["test"] = "initial value";

        Console.WriteLine(u.Name);

        Console.WriteLine(u.Map["test"]);

        Modify(u);

        Console.WriteLine(u.Name);

        Console.WriteLine(u.Map["test"]);

    }

    public static void Modify(User u)

    {

        u.Name = "Second User";

        u.Map["test"] = "second value";

    }

}