how to set the tab name of a browser based on file name

public string DownloadAttachment()
        {
            string filepath = new FileInfo(HttpContext.Current.Server.MapPath("Ticket")).FullName +"\\"+ GetPageParams<string>("hdnAttachmentID");          
            string fileExtension = Path.GetExtension(GetPageParams<string>("hdnAttachmentID"));            
            string viewname = "TicketUpdateDetailView";
            try
            {
                HttpContext.Current.Response.Clear();
                HttpContext.Current.Response.WriteFile(filepath);
                switch (fileExtension)
                {


                    case ".jpg":
                    case ".jpeg":
                        {
                            HttpContext.Current.Response.ContentType = "image/jpeg";
                            HttpContext.Current.Response.AppendHeader("Content-disposition", "inline;filename=" + Path.GetFileName(filepath));
                            break;
                        }
                    case ".bmp":
                        {
                            HttpContext.Current.Response.ContentType = "image/bmp";
                            HttpContext.Current.Response.AppendHeader("Content-disposition", "inline;filename=" + Path.GetFileName(filepath));
                            break;
                        }
                    case ".gif":
                        {
                            HttpContext.Current.Response.ContentType = "image/gif";
                            HttpContext.Current.Response.AppendHeader("Content-disposition", "inline;filename=" + Path.GetFileName(filepath));
                            break;
                        }
                    case ".png":
                        {
                            HttpContext.Current.Response.ContentType = "image/png";
                            HttpContext.Current.Response.AppendHeader("Content-disposition", "inline;filename=" + Path.GetFileName(filepath));
                            break;
                        }
                    default:
                        {
                            HttpContext.Current.Response.ContentType = "application/octet-stream";
                            HttpContext.Current.Response.AppendHeader("content-disposition", "attachment;filename=" + Path.GetFileName(filepath));
                            break;
                        }
                }
                //HttpContext.Current.Response.ContentType = "application/octet-stream";
                //HttpContext.Current.Response.AppendHeader("content-disposition", "attachment; filename=" + Path.GetFileName(fileFullPath));                               
                //var pageTitle = (Page)HttpContext.Current.Handler;                
                //pageTitle.Title=Path.GetFileName(fileFullPath);
                HttpContext.Current.Response.End();
                viewname = "TicketUpdateDetailView";
            }
            catch (System.Threading.ThreadAbortException ex1)
            {

            }
            catch (Exception ex)
            {

            }
            return viewname;
        }