public static void WriteDown(string filePath, string filename)
{
HttpContext.Current.Response.Buffer = true;
HttpContext.Current.Response.Clear();
HttpContext.Current.Response.ContentType = GetResponseContentType(Path.GetExtension(filePath));
HttpContext.Current.Response.AddHeader("Content-Disposition", "attachment; filename=" + FPUtils.UrlEncode(filename));
HttpContext.Current.Response.WriteFile(filePath);
HttpContext.Current.Response.Flush();
HttpContext.Current.Response.End();
}