How to show a save dialog box when a link with .swf file is clicked?

 try
            {
                HtmlAnchor anchor = (HtmlAnchor)sender;
                System.IO.FileInfo targetfile = new System.IO.FileInfo(anchor.HRef);

                if (targetfile.Exists)
                {
                    Response.Clear();
                    Response.AddHeader("Content-Disposition", "attachment; filename=" + targetfile.Name);
                    Response.AddHeader("Content-Length", targetfile.Length.ToString());
                    Response.ContentType = "application/x-shockwave-flash";
                    Response.WriteFile(targetfile.FullName);
                }
            }
            catch (Exception ex)
            {
                LogException(ex);
            }