如果你不能使用JSON命名空间或库来反序列化数据，你可以手动解析JSON字符串来实现。这需要用到一些基本的字符串操作和条件语句。

以下是一个示例解决方案的代码示例：

using System;
using System.Collections.Generic;

public class Program
{
    public static void Main()
    {
        string json = @"{
            ""name"": ""John Smith"",
            ""age"": 30,
            ""email"": ""john.smith@example.com"",
            ""hobbies"": [""reading"", ""writing"", ""playing guitar""]
        }";

        Dictionary data = DeserializeJson(json);
        Console.WriteLine("Name: " + data["name"]);
        Console.WriteLine("Age: " + data["age"]);
        Console.WriteLine("Email: " + data["email"]);
        Console.Write("Hobbies: ");
        foreach (var hobby in (List