How to download Excel from Webpage

public void DownloadFile(string filePath)
        {
            if (File.Exists(Server.MapPath(filePath)))
            {
                string strFileName = Path.GetFileName(filePath).Replace(" ", "%20");
                Response.ContentType = "application/octet-stream";
                Response.AddHeader("Content-Disposition", "attachment; filename=" + strFileName);
                Response.Clear();
                Response.WriteFile(Server.MapPath(filePath));
                Response.End();
            }
        }