更新gridview中的值不起作用

Question

gridview中有一行，其中列名为POA_NO，其值为899。

但我正在删除该值并将其更新为空白。但它仍然只更新为899。

这是我的代码

protected void GrdDetail_UpdateCommand(object sender, GridRecordEventArgs e)
{
    if (Session["ViewInfo"] != null)
    {
        dtViewInfo = (DataTable)Session["ViewInfo"];
    }
    else
    {
        return;
    }

    DataRow[] drViewInfo = dtViewInfo.Select("SR_NO = " + e.Record["SR_NO"]);

    if (e.Record["TYPE"] != "")
    {
        drViewInfo[0]["TYPE"] = e.Record["TYPE"];
    }
    else
    {
        drViewInfo[0]["TYPE"] = "NULL";
    }

    if (e.Record["REF_NO"] != "")
    {
        drViewInfo[0]["REF_NO"] = e.Record["REF_NO"];
    }
    if (e.Record["REF_DATE"] != "")
    {
        drViewInfo[0]["REF_DATE"] = e.Record["REF_DATE"];
    }
    if (e.Record["POA_NO"] != "")
    {
        drViewInfo[0]["POA_NO"] = e.Record["POA_NO"];
    }
    if (e.Record["POA_DATE"] != "")
    {
        drViewInfo[0]["POA_DATE"] = e.Record["POA_DATE"];
    }
    if (e.Record["POA_NAME"] != "")
    {
        drViewInfo[0]["POA_NAME"] = e.Record["POA_NAME"];
    }

    if (e.Record["ATTACHMENT"] != "")
    {
        drViewInfo[0]["ATTACHMENT"] = e.Record["ATTACHMENT"];
    }

    GrdDetail.DataSource = dtViewInfo;
    GrdDetail.DataBind();
    AddToViewState("GridViewInfo");
}

修改

页面加载代码

dtViewInfo = CF.ExecuteDT("select sr_no, type, ref_no, to_char (ref_date,'dd/MM/yyyy') ref_date, POA_NO , to_char (POA_DATE, 'dd/MM/yyyy')   POA_DATE, POA_NAME, attachment from xxcus.XXACL_PN_VIEW_DATA_INFO " +
                              "where mkey = '" + StrMkey + "' order by   sr_no");


    GrdDetail.DataSource = dtViewInfo;
    GrdDetail.DataBind();
    AddToViewState("GridViewInfo");