[WCF] 服务器未提供有意义的回复；这可能是由协定不匹配、会话过早关闭或内部服务器错误引起的。

Question

服务器未提供有意义的回复；这可能是由协定不匹配、会话过早关闭或内部服务器错误引起的。
这是什么意思?代码:using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.Text;namespace Common //公用包
{
    [Serializable]
    public enum UserAction:byte
    {
        Gone            =1,
        Entered         =2,
        FinishedAnswer  =3
    }    [ServiceContract(CallbackContract = typeof(IServiceCallBack))]
    public interface IService
    {
        [OperationContract]
        void Unregister(Guid id);        [OperationContract]
        Guid Register(String name);        [OperationContract]
        void Say(Guid from,Guid target, String message);        [OperationContract]
        UserList GetNewestUserList();
    }    public interface IServiceCallBack
    {
        [OperationContract]
        void ReceiveMessage(User user, String message);        [OperationContract]
        void UserAction(User user, UserAction action);
    }
    [DataContract]
    public class User:IEquatable<Guid>
    {
        [DataMember]
        String username;        [DataMember]
        Guid userId = Guid.NewGuid();        public User(String username)
        {
            this.username = username;        }                
        public String UserName
        {
            get { return username; }
        }
        
        public Guid UserId
        {
            get { return userId; }
        }        public override string ToString()
        {
            return UserName;
        }        #region IEquatable<Guid> 成员        public bool Equals(Guid other)
        {
            return UserId == other;
        }        #endregion
    }
    [DataContract]
    public class UserList
    {
        User[] users= new User[0];        [DataMember]
        public User[] Users
        {
            get { return users; }
            set { users = value; }
        }
        public void Add(User u)
        {
            Array.Resize<User>(ref users, users.Length+1);
            users[users.Length - 1] = u;
        }
        public void Remove(User u)
        {
            int index=0;
            if ((index = Array.IndexOf(users, u)) > -1)
            {
                while (index++ < users.Length)
                    users[index - 1] = users[index];                Array.Resize<User>(ref users, index - 1);
            }
        }        
        public Int32 Count
        {
            get { return users.Length; }
        }        
        public User this[int index]
        {
            get 
            {
                if (index > users.Length - 1)
                    throw new IndexOutOfRangeException();                return users[index];
            }
            set
            {
                if (index > users.Length - 1)
                    throw new IndexOutOfRangeException();                users[index] = value;
            }
        }        
        public User this[Guid index]
        {
            get
            {
                foreach (User u in users)
                    if (u.Equals(index))
                        return u;                return null;
            }
        } 
        public Int32 IndexOf(User u)
        {
            return Array.IndexOf<User>(users, u);
        }
    }
}
namespace Srv //服务器
{
    /// <summary>
    /// This is the implementation of IService. We have to keep this in the server.
    /// So the server can use the stub in BaseService to call client.
    /// </summary>
    [ServiceBehavior(InstanceContextMode = InstanceContextMode.Single,IncludeExceptionDetailInFaults=true)]
    public class BaseService : IService
    {
        #region IService Member
        //public IServiceCallBack callback;
        List<UserInfo> stubs = new List<UserInfo>();        public BaseService()
        {
            //this.s = c;
        }        private UserInfo FindUser(Guid g)
        {
            var foundStubs = from s in stubs where s.UserId == g select s;            List<UserInfo> info = foundStubs.ToList<UserInfo>();            Debug.Assert(info.Count <= 1);            if (info.Count == 0)
                return null;
            else
                return info[0];
        }        public void Unregister(Guid id)
        {
            stubs.Remove(FindUser(id));            foreach (UserInfo info in stubs)
                info.Callback.UserAction(info, UserAction.Gone);
        }        public Guid Register(string name)
        {
           IServiceCallBack callback = OperationContext.Current.GetCallbackChannel<IServiceCallBack>();           UserInfo newuser = new UserInfo(name,callback);
            //Client registed!!
            if (callback != null)
                this.stubs.Add(newuser);            foreach (UserInfo info in stubs)
            {
                if (info == newuser)
                    continue;                info.Callback.UserAction(newuser, UserAction.Entered);
            }            return newuser.UserId;        }        public void Say(Guid from,Guid target, String message)
        {            if (target != Guid.Empty)
            {
                UserInfo info = FindUser(target);                if(info!=null)
                    info.Callback.ReceiveMessage(FindUser(from), message);
            }
            else
            {
                foreach (UserInfo info in stubs)
                    info.Callback.ReceiveMessage(FindUser(from), message);
            }
        }        public UserList GetNewestUserList()
        {
            UserList list = new UserList();
            foreach (UserInfo user in stubs)
                list.Add(user);
            return list;
        }        #endregion    }   ....
    
   [ServiceKnownType(typeof(User))]
    public class UserInfo : User
    {
        public UserInfo(String name, IServiceCallBack callback)
            : base(name)
        {
            this.callback = callback;
        }        IServiceCallBack callback;        
        internal IServiceCallBack Callback
        {
            get { return callback; }
        }    }   ....
}
客户端调用顺序: Register() --> GetNewestUserList()
客户端在调用Register时候没问题
调用GetNewestUserList时候就会报错:
System.ServiceModel.CommunicationException: 服务器未提供有意义的回复；这可能是由协定不匹配、会话过早关闭或内部服务器错误引起的。怎么回事? 请各位大师不吝赐教! 谢谢

Answer 1

你的UserList没有标记成可序列化：[Serializable]

Answer 2

没用过WCF就别乱说。你缺少了一个[ServiceContract]说明，这是必须的，参考代码：
    [ServiceContract]
    public interface IServiceCallBack
    {
        [OperationContract]
        void ReceiveMessage(User user, String message);        [OperationContract]
        void UserAction(User user, UserAction action);
    }

Answer 3

服务器端配置问题，应该是调用服务器都相关关闭了
还有就是ServiceBehavior配置问题
参考

Answer 4

汗死 问题解决了.
WCF中不允许在协议中定义一个类型而传输其子类型. 除非在该类型上定义了[KnownType(typeof(子类型))]这个错误犯得够幼稚的

Answer 5

为了避免恶意攻击网站，WCF服务只向客户端返回及其简单的异常信息，使得你无法通过客户端来调试发现服务器异常。此时要调试查看WCF服务，可以看msdn:http://msdn.microsoft.com/zh-cn/library/ms732023.aspx