Json.NET技巧-反序列化還原為不同型別的集合

using Newtonsoft.Json;

using Newtonsoft.Json.Converters;

using System;

namespace CustCreate

{

    public enum Channels

    {

        Email, SMS

    }

    //通知作業

    public abstract class Notification

    {

        [JsonConverter(typeof(StringEnumConverter))]

        //通知管道

        public Channels JobType { get; protected set; }

        //排程時間

        public DateTime ScheduledTime { get; set; }

        //訊息內容

        public string Message { get; set; }

        protected Notification(DateTime time, string msg)

        {

            ScheduledTime = time;

            Message = msg;

        }

        protected Notification() { }

    }

    //電子郵件通知

    public class EmailNotification : Notification

    {

        public string Email { get; set; }

        public EmailNotification(DateTime time, string email, string msg)

            : base(time, msg)

        {

            JobType = Channels.Email;

            Email = email;

        }

    }

    //簡訊通知

    public class SMSNotification : Notification

    {

        //電話號碼

        public string PhoneNo { get; set; }

        public SMSNotification()

        {

            JobType = Channels.SMS;

        }

        public SMSNotification(DateTime time, string phoneNo, string msg)

            : base(time, msg)

        {

            JobType = Channels.SMS;

            PhoneNo = phoneNo;

        }

    }

}

    var jobs = new List<Notification>();

    jobs.Add(new EmailNotification(

        DateTime.UtcNow, "blah@bubu.blah.boo", "Test 1"));

    jobs.Add(new SMSNotification(

        DateTime.UtcNow, "0912345678", "Test 2"));

    Console.WriteLine(

        JsonConvert.SerializeObject(jobs, Formatting.Indented));

    Console.Read();

using Newtonsoft.Json;

using Newtonsoft.Json.Converters;

using Newtonsoft.Json.Linq;

using System;

using System.Collections.Generic;

namespace CustCreate

{

    class Program

    {

        static string json = @"[

  {

    ""Email"": ""blah@bubu.blah.boo"",

    ""JobType"": ""Email"",

    ""ScheduledTime"": ""2013-12-13T13:43:25.6881876Z"",

    ""Message"": ""Test 1""

  },

  {

    ""PhoneNo"": ""0912345678"",

    ""JobType"": ""SMS"",

    ""ScheduledTime"": ""2013-12-13T13:43:25.6891803Z"",

    ""Message"": ""Test 2""

  }

]";

        //自訂轉換器，繼承CustomCreationConverter<T>

        class NotificationConverter : CustomCreationConverter<Notification>

        {

            //由於ReadJson會依JSON內容建立不同物件，用不到Create()

            public override Notification Create(Type objectType)

            {

                throw new NotImplementedException();

            }

            //自訂解析JSON傳回物件的邏輯

            public override object ReadJson(JsonReader reader, Type objectType, 

                object existingValue, JsonSerializer serializer)

            {

                JObject jo = JObject.Load(reader);

                //先取得JobType，由其決定建立物件

                string jobType = jo["JobType"].ToString();

                if (jobType == "Email")

                {

                    //做法1: 由JObject取出建構式所需參數建構物件

                    var target = new EmailNotification(

                            jo["ScheduledTime"].Value<DateTime>(),

                            jo["Email"].ToString(),

                            jo["Message"].ToString()

                        );

                    return target;

                }

                else if (jobType == "SMS")

                {

                    //做法2: 若物件支援無參數建構式，則可直接透過

                    //       serializer.Populate()自動對應屬性

                    var target = new SMSNotification();

                    serializer.Populate(jo.CreateReader(), target);

                    return target;

                }

                else

                    throw new ApplicationException("Unsupported type: " + jobType);

            }

        }

        static void Main(string[] args)

        {

            //JsonConvert.DeserializeObject時傳入自訂Converter

            var list = JsonConvert.DeserializeObject<List<Notification>>(

                json, new NotificationConverter());

            var item = list[0];

            Console.WriteLine("Type:{0} Email={1}", 

                item.JobType, (item as EmailNotification).Email);

            item = list[1];

            Console.WriteLine("Type:{0} PhoneNo={1}", 

                item.JobType, (item as SMSNotification).PhoneNo);

            Console.Read();

        }

    }

}