操作JSON字符串

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using Newtonsoft.Json;
using Newtonsoft.Json.Converters;
using System.Runtime.Serialization;
using System.IO;

namespace JobSearch
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Product pro = new Product();
            pro.Name = "show";
            pro.Size = 70;
            pro.ProcductDate = DateTime.Now.AddDays(-10);
            IList<Product> ProductCollection = new List<Product>();
            ProductCollection.Add(pro);
            ProductCollection.Add(pro);
            ProductCollection.Add(pro);
            string JsonStr = JsonConvert.SerializeObject(ProductCollection);
            //string JsonStr = JsonHelper.Serialize(ProductCollection);
            this.textBox1.Text = JsonStr;

        }

        private void button2_Click(object sender, EventArgs e)
        {
            string JsonStr = this.textBox1.Text;
            IList<Product> ProductCollection = (IList<Product>)JsonConvert.DeserializeObject(JsonStr, typeof(IList<Product>));
            //Product pro = (Product)JsonConvert.DeserializeObject(JsonStr, typeof(Product));
            MessageBox.Show(ProductCollection.Count.ToString());
        }
    }
    [Serializable]
    public class Product
    {
        private string _Name = string.Empty;

        public string Name
        {
            get { return _Name; }
            set { _Name = value; }
        }
        private int _Size = 0;

        public int Size
        {
            get { return _Size; }
            set { _Size = value; }
        }
        private DateTime _ProcductDate = DateTime.MinValue;

        public DateTime ProcductDate
        {
            get { return _ProcductDate; }
            set { _ProcductDate = value; }
        }

    }


    public class JsonHelper
    {
        public static string Serialize<T>(T data)
        {
            System.Runtime.Serialization.Json.DataContractJsonSerializer serializer = new System.Runtime.Serialization.Json.DataContractJsonSerializer(data.GetType());
            using (MemoryStream ms = new MemoryStream())
            {
                serializer.WriteObject(ms, data);
                return Encoding.UTF8.GetString(ms.ToArray());
                //ms.Position = 0;
                //using (StreamReader sr = new StreamReader(ms))
                //{
                //    return sr.ReadToEnd();
                //}
            }
        }

        public static T Deserialize<T>(string json)
        {
            T obj = Activator.CreateInstance<T>();
            using (MemoryStream ms = new MemoryStream(Encoding.UTF8.GetBytes(json)))
            {
                System.Runtime.Serialization.Json.DataContractJsonSerializer serializer = new System.Runtime.Serialization.Json.DataContractJsonSerializer(obj.GetType());
                return (T)serializer.ReadObject(ms);
            }
        }
    }
}