Android访问WCF得到的奇怪Json

操作契约:        [OperationContract]
        [WebInvoke(
            BodyStyle = WebMessageBodyStyle.WrappedRequest,
            ResponseFormat = WebMessageFormat.Json,
            RequestFormat = WebMessageFormat.Json)]
        RetUserInform logIn(string userID, string PWD);
服务实现  #region IAndroidServices Members logIn        public RetUserInform logIn(string userID, string PWD)
        {
            Console.WriteLine("logIn has bean satared");
            RetUserInform n = new RetUserInform();
            n.Userid = 123456;
            n.Functions = "asdfads";
            n.UserAreaCode = "012";
            n.FinalDate = "afd";
            return n;
        }        #endregion实体类     [DataContract]
    public class RetUserInform
    {
        [DataMember(Name = "Userid")]
        public int Userid
        {
            get;
            set;
        }
        [DataMember (Name = "Functions")]
        public string Functions
        {
            get;
            set;
        }
        [DataMember (Name = "FinalDate")]
        public string FinalDate
        {
            get;
            set;
        }        [DataMember(Name = "UserAreaCode")]
        public String UserAreaCode
        {
            get;
            set;
        }    }
问题: 在android端得到返回的Json如下{"d":{"__type":"RetUserInform:#Host","FinalDate":"afd","Functions":"asdfads","UserAreaCode":"012","Userid":123456}}
那个奇怪的d是什么东西啊? 在Android端如果使用GSON解析的话应该怎么处理呢?