akpaga22

but i already have my excel export working in standard fromat  which i cannot change

Then I think you can do this trick：

1）In the Page_Load event handler，please dynamically generate a GridView：

if(!IsPostBack)｛GridView gv = new GridView(); gv.DataSource=yourDataTable;gv.DataBind();｝

2）And then use the codes I've told you above to export to a whole excel file：

Response.Clear();

        Response.AddHeader("content-disposition", "attachment;
        filename=FileName.xls");

        Response.Charset = "";

        // If you want the option to open the Excel file without saving than

        // comment out the line below

        // Response.Cache.SetCacheability(HttpCacheability.NoCache);

        Response.ContentType = "application/vnd.xls";

        System.IO.StringWriter stringWrite = new System.IO.StringWriter();

        System.Web.UI.HtmlTextWriter htmlWrite =
        new HtmlTextWriter(stringWrite);

        GridView1.RenderControl(htmlWrite);

        Response.Write(stringWrite.ToString());

        Response.End();

public override void VerifyRenderingInServerForm(Control control)
    {

        // Confirms that an HtmlForm control is rendered for the
        specified ASP.NET server control at run time.

    }