protected string GetUserPreName(int id)
        {
            BLL.users bll     = new BLL.users();
            string    preName = string.Empty;

            DataTable dt = bll.GetPreUserInfo(id).Tables[0];//获取该用户上线信息

            if (dt.Rows.Count > 0)
            {
                preName = dt.Rows[0]["nick_name"].ToString();
            }
            else
            {
                preName = "暂无上线";
            }

            return(preName);
        }