求教:.net+access不能实现数据库数据的修改

使用三层体系结构IDAL+DBUTILITY+OLEDBDAL+DALFACTORY+BLL+WEB
  OleDbDal中 定义了updateUserPassword(int userid, string newpassword)如下      /// <summary>
        /// 修改密码
        /// </summary>
        /// <param name="userid">用户编号</param>
        /// <param name="newpassword">新密码</param>
        /// <returns></returns>
        public int updateUserPassword(int userid, string newpassword)
        {
            StringBuilder sb = new StringBuilder();
            sb.Append(" update userinfo set [password]=@newpassword where [userid]=@userid");
            OleDbParameter[] param = 
                                   { 
                                       OleDbHelper.GetParameter("@userid", OleDbType.Integer, 4, "[userid]", userid) ,
                                       OleDbHelper.GetParameter("@newpassword",OleDbType.Char,50,"[password]",newpassword)
                                   };
            return OleDbHelper.ExecuteSql(sb.ToString(), param);
        }调用OleDbHelper类中的
 /// <summary>
    /// 执行SQL语句
    /// </summary>
    /// <param name="Sqlstr">SQL语句</param>
    /// <param name="param">参数对象数组</param>
    /// <returns></returns>
    public static int ExecuteSql(String Sqlstr, OleDbParameter[] param)
    {
        String ConnStr = OleDbHelper.GetSqlConnection();
        using (OleDbConnection conn = new OleDbConnection(ConnStr))
        {
            OleDbCommand cmd = new OleDbCommand();
            cmd.Connection = conn;
            cmd.CommandText = Sqlstr;
            cmd.Parameters.AddRange(param);            conn.Open();
           
            try
            {
                cmd.ExecuteNonQuery();                return 1;
            }
            catch (System.Data.OleDb.OleDbException ex)
            {                return 0;
                    throw new Exception(ex.Message);
               
            }
            finally
            {
                conn.Close();
            }
        }web页实现密码修改按钮点击事件
 /// <summary>
        /// 修改密码
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        protected void updateBt_Click(object sender, EventArgs e)
        {
          if (user.validUser(user.getUserName(), this.oldpasswordTb.Text.Trim(), 1) == true)
            {
                if(user.updateUserPassword(user.getUserID(), this.newpasswordTb.Text.Trim())==1)
                    Page.ClientScript.RegisterStartupScript(this.GetType(), "", "<script   language='javascript'>alert('yeal!');</script>"); 
            }
            else
            {
                Page.ClientScript.RegisterStartupScript(this.GetType(), "", "<script   language='javascript'>alert('旧密码错误!');</script>"); 
            }          
        }运行弹出"修改"成功,而查看数据库却发现数据没有改变.什么原因呢?所有修改都似乎有这个问题!!!请帮帮我呀!!急呀!!