MSMQ接受时出现错误

using System;using System.Linq;using System.Messaging;namespace MSMQ{    public delegate void Deal(string msg);    public class DbQueue    {        public MessageQueue mq;        public Deal deal;        public ReceiveCompletedEventHandler deal2;        public DbQueue()        {            try            {                if (MessageQueue.Exists(@".\Private$\DBWrite"))                    mq = new MessageQueue(@".\Private$\DBWrite");                else                    mq = MessageQueue.Create(@".\Private$\DBWrite");            }            catch (MessageQueueException e)            {                Console.WriteLine(e.Message);            }        }        public void Send(string msg)        {            mq.Send(msg);            Console.WriteLine("发送消息：" + msg);        }        public void Receive()        {            while (true)            {                while (mq.GetAllMessages().Count() > 0)                {                    Console.Write("共有" + mq.GetAllMessages().Count().ToString() + "条");                    //Message msg = mq.Receive();       //同步接收                    mq.BeginReceive();                    mq.ReceiveCompleted += deal2;                    //Object obj = msg.Body;                    //deal(obj.ToString());                }                Console.WriteLine("等待中");            }        }        public void ReadAll()        {            foreach (Message m in mq)            {                string result = m.Body.ToString();                Console.WriteLine(result);            }        }    }}

using System;namespace MSMQ{    class Program    {        static void Main(string[] args)        {            DbQueue q = new DbQueue();            while (true)            {                Console.Write("输入发送字符串：");                string msg=Console.ReadLine();                q.Send(msg);                q.ReadAll();            }            Console.ReadKey();        }            }    }

using System;using MSMQ;using System.Threading;using System.Messaging;namespace MSMQ_receiver{    class Program    {        static void Main(string[] args)        {            DbQueue db = new DbQueue();            db.deal = new Deal(ConcentDeal);            db.deal2 = new ReceiveCompletedEventHandler(MyAsyncReceiver);            Thread me = new Thread(new ThreadStart(db.Receive));            me.Start();            //db.ReadAll();        }        public static void ConcentDeal(string msg)        {            Console.WriteLine("处理中……");            Thread.Sleep(new Random().Next(1000));            Console.WriteLine("收到消息：" + msg);        }        public static void MyAsyncReceiver(object resouce,ReceiveCompletedEventArgs args)        {            MessageQueue mq=resouce as MessageQueue;            Message obj=mq.EndReceive(args.AsyncResult);          //就是这里异常了            Console.WriteLine("收到的消息为："+obj.Body.ToString());   //这里报错：找不到能够读取此消息的格式化程序。        }    }    }