Exporting Data from Grid to Excel

Hi All,
Below is the piece of code through which I was exporting data from gridview control to excel sheet. Grid data is getting exported correctly and I need to add filter functionality to excel sheet in the header row for every column in the button click event itself.
How could I achieve this?

 protected void lbtnExportExcelAll_OnClick(object sender, EventArgs e)
        {

            //exporting data to excel document//
            GridView gridview1 = new GridView();
            gridview1.DataSource = DischargePatientRecordsForRightFilters;
            Response.ClearContent();
            Response.Buff ...