protected void BT_Export_CSV_Click(object sender, EventArgs e)
{
Media media = DataMapping.ExportDataGridToXLS(GridView1, "Statistiques.csv", Aspose.Cells.SaveFormat.CSV);
string guid = Guid.NewGuid().ToString();
Session[guid] = media;
Response.Redirect(Const.MEDIA_DOWNLOAD_URL + "?id=" + guid);
}