How to avoid exporting certain column headers from exporting in ASP.Net GridView

I have boundfiled column inside gridview and made the column as invisible by setting visible="false".

But while exporting the gridview to excel I am getting the Header text alone exported. Wherever the column's visibility is set to false the header text should not be exported. After binding the gridview I have set the column's visiblity to false so it won't export the column values.

The problem is to stop exporting the header text to excel. Let's say column index is 10

public class GridViewExportUtil  
{  
  
    public static void Export(string fileName, GridView gv)  
    {  
        HttpContext.Current.Response.Clear();  
        HttpContext.Current.Response.AddHeader(  
            "content-disposition", string.Format("attachment; filename={0}", fileName));  
        HttpContext.Current.Response.ContentType = "application/ms-excel";  
  
        using (StringWriter sw = new StringWriter())  
        {  
            using (HtmlTextWriter htw = new HtmlTextWriter(sw))  
            {  
                //  Create a form to contain the grid  
                Table table = new Table();  
  
                //  add the header row to the table  
                if (gv.HeaderRow != null)  
                {  
                    GridViewExportUtil.PrepareControlForExport(gv.HeaderRow);  
                    table.Rows.Add(gv.HeaderRow);  
                }  
  
                //  add each of the data rows to the table  
                foreach (GridViewRow row in gv.Rows)  
                {  
                    GridViewExportUtil.PrepareControlForExport(row);  
                    table.Rows.Add(row);  
                }  
  
                //  add the footer row to the table  
                if (gv.FooterRow != null)  
                {  
                    GridViewExportUtil.PrepareControlForExport(gv.FooterRow);  
                    table.Rows.Add(gv.FooterRow);  
                }  
  
                //  render the table into the htmlwriter  
                table.RenderControl(htw);  
  
                //  render the htmlwriter into the response  
                HttpContext.Current.Response.Write(sw.ToString());  
                HttpContext.Current.Response.End();  
            }  
        }  
    }  
  
    /// <summary>  
    /// Replace any of the contained controls with literals  
    /// </summary>  
    /// <param name="control"></param>  
    private static void PrepareControlForExport(Control control)  
    {  
        for (int i = 0; i < control.Controls.Count; i++)  
        {  
            Control current = control.Controls[i];  
            if (current is LinkButton)  
            {  
                control.Controls.Remove(current);  
                control.Controls.AddAt(i, new LiteralControl((current as LinkButton).Text));  
            }  
            else if (current is ImageButton)  
            {  
                control.Controls.Remove(current);  
                control.Controls.AddAt(i, new LiteralControl((current as ImageButton).AlternateText));  
            }  
            else if (current is HyperLink)  
            {  
                control.Controls.Remove(current);  
                control.Controls.AddAt(i, new LiteralControl((current as HyperLink).Text));  
            }  
            else if (current is DropDownList)  
            {  
                control.Controls.Remove(current);  
                control.Controls.AddAt(i, new LiteralControl((current as DropDownList).SelectedItem.Text));  
            }  
            else if (current is CheckBox)  
            {  
                control.Controls.Remove(current);  
                control.Controls.AddAt(i, new LiteralControl((current as CheckBox).Checked ? "True" : "False"));  
            }  
  
            if (current.HasControls())  
            {  
                GridViewExportUtil.PrepareControlForExport(current);  
            }  
        }  
    }  
}