取不到girdview隐藏列的数据?

<asp:GridView ID="gvconfig" runat=server Width=500px AutoGenerateColumns="False" DataKeyNames="PARAM_VALUE" HorizontalAlign="Center" OnRowDeleting="gvconfig_RowDeleting" OnRowEditing="gvconfig_RowEditing" OnRowCancelingEdit="gvconfig_RowCancelingEdit" OnRowUpdating="gvconfig_RowUpdating" CellPadding="3">
                    <Columns>
                        <asp:BoundField DataField="param_name" HeaderText="配置名称">
                            <ItemStyle Width="320px" />
                        </asp:BoundField>                       
                        <asp:CommandField ButtonType="Image" ShowEditButton="True" EditImageUrl="../images/edit_button.gif" CancelImageUrl="../images/cancel_button.gif" UpdateImageUrl="../images/update_button.gif" />
                        <asp:CommandField ButtonType="Image" DeleteImageUrl="../images/delete_button.gif" ShowDeleteButton="True" />
                        <asp:BoundField DataField="param_type" Visible="False" />
                        <asp:BoundField DataField="param_value" Visible="False" />
                        <asp:BoundField DataField="param_name" Visible="False" />
                    </Columns>
                    <RowStyle Height="22px" />
                    <HeaderStyle BackColor="#E2F1FF" Height="24px" />
                    <AlternatingRowStyle BackColor="WhiteSmoke" />     
            </asp:GridView>---------------------------------------------------------------------- protected void gvconfig_RowUpdating(object sender, GridViewUpdateEventArgs e)
    {
        try
        {
            JHXT_PARAM.updParamsRecords(this.gvconfig.Rows[e.RowIndex].Cells[3].Text, 
                this.gvconfig.Rows[e.RowIndex].Cells[4].Text,
                this.dlitem.SelectedItem.Value, 
                JHXT_PARAM.retNo(this.dlitem.SelectedItem.Value),
                ((TextBox)this.gvconfig.Rows[e.RowIndex].Cells[0].Controls[0]).Text.Trim()
                );            
        }
        catch (System.Exception ex)
        {
            SysLog.Logger("ConfigParam.aspx", ex.ToString());
            this.Page.ClientScript.RegisterStartupScript(this.GetType(), "Error", "<script>alert('出现数据异常，请联系管理员！');</script>");
            return;
        }
        Utility.MsgBox(this.Page, "已经成功编辑配置信息！", false);
        this.gvconfig.EditIndex = -1;
        this.bindDATA();        
    }------------------------------------------------------------------------this.gvconfig.Rows[e.RowIndex].Cells[3].Text 
this.gvconfig.Rows[e.RowIndex].Cells[4].Text这两列的数据取不到，取出来是空的，帮我看看，谢谢！