//
引用
using System.IO;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Json;

------解决方案--------------------

C# code

//最后改了下

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

namespace ConsoleApplication1
{
    [DataContract]
    public sealed class FooDef
    {
        [DataMember(Name = "ID", IsRequired = true)]
        public string ID { get; set; }

        [DataMember(Name = "Order", IsRequired = true)]
        public string Order { get; set; }
    }

    class Program
    {
        static void Main(string[] args)
        {
            string bar = "[{\"ID\":\"3\",\"Order\":\"9\"},{\"ID\":\"1\",\"Order\":\"6\"},{\"ID\":\"2\",\"Order\":\"8\"}]";
            List<FooDef> newEntities = Deserialize<FooDef>(bar);
            var s = from l in newEntities orderby l.ID select l;
        }
        static List<T> Deserialize<T>(string str)
        {
            DataContractJsonSerializer json = new DataContractJsonSerializer(typeof(List<T>));
            using (MemoryStream stream = new MemoryStream(Encoding.UTF8.GetBytes(str)))
            {
                List<T> entities = (List<T>)json.ReadObject(stream);
                stream.Close();
                return entities;
            }
        }
    }
}