how to download in asp.net C# website

 public static string ServerMapPath(string path)
    {
        return HttpContext.Current.Server.MapPath(path);
    }
    public static HttpResponse GetHttpResponse()
    {
        return HttpContext.Current.Response;
    }
    public static void DownLoadFileFromServer(string fileName)
    {
        //This is used to get Project Location.
        try
        {
            string filePath = ServerMapPath(fileName);
            //This is used to get the current response.
            HttpResponse res = GetHttpResponse();
            res.Clear();
            res.AppendHeader("content-disposition", "attachment; filename=" + filePath);
            res.ContentType = "application/octet-stream";
            res.WriteFile(filePath);
            res.Flush();
            res.End();
        }
        catch (Exception ex)
        {
           
        }
    }

 protected void Button2_Click(object sender, EventArgs e)
    {
DownLoadFileFromServer("~/Storage/" + txtname.Text);
}