如何使用DataContractJsonSerializer反序列化字典？

using System;
using System.IO;
using System.Runtime.Serialization.Json;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        string json = "{\"key1\":\"value1\",\"key2\":\"value2\",\"key3\":\"value3\"}";

        Dictionary<string, string> dictionary = DeserializeDictionary(json);

        foreach (var item in dictionary)
        {
            Console.WriteLine(item.Key + ": " + item.Value);
        }
    }

    static Dictionary<string, string> DeserializeDictionary(string json)
    {
        using (MemoryStream stream = new MemoryStream(System.Text.Encoding.UTF8.GetBytes(json)))
        {
            DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(Dictionary<string, string>));
            return (Dictionary<string, string>)serializer.ReadObject(stream);
        }
    }
}