为显示客户端IP,我先在CarManage.cx中增加

private string ip = "";

  
  /// <summary>
    /// card_ip
    /// </summary>
    public string ip
    {
        get { return ip; }
        set { ip = value; }
    }

 public int AddCard(CardManage cardmanage)
    {
        SqlParameter[] prams = {
    data.MakeInParam("@cardid",  SqlDbType.NVarChar, 50, cardmanage.CardID),
                                        data.MakeInParam("@cardname",  SqlDbType.NVarChar, 1000, cardmanage.CardName),
                 data.MakeInParam("@moduleid",  SqlDbType.NVarChar, 50,cardmanage.ModuleID),
                 data.MakeInParam("@cardcontent",  SqlDbType.NVarChar, 4000, cardmanage.CardContent),
                 data.MakeInParam("@cardtime",  SqlDbType.SmallDateTime, 8, cardmanage.CardTime),
                 data.MakeInParam("@cardpeople",  SqlDbType.NVarChar, 50, cardmanage.CardPeople),
                                        data.MakeInParam("@pop",  SqlDbType.NChar, 10, cardmanage.Pop),
                                      
                                        data.MakeInParam("@ip",  SqlDbType.NVarChar, 50, cardmanage.ip),
};
        return (data.RunProc("INSERT INTO tb_Card (帖子编号,帖子名称,版块编号,帖子内容,发表时间,发帖人,角色,card_ip) VALUES (@cardid,@cardname,@moduleid,@cardcontent,@cardtime,@cardpeople,@pop,@ip)", prams));
    }


然后在delivercard.aspx中加入

 cardmanage.ip = Session["IP"].ToString();


（先已声明：  Session["IP"] = Request.UserHostAddress.ToString();）
有下面文句时，
   /// <summary>
    /// card_ip
    /// </summary>
    public string ip
    {
        get { return ip; }
        set { ip = value; }
    }
提示：“CardManage”已经包含“ip”的定义

无上面语句时：

提示：“CardManage”并不包含“ip”的定义

为什么？