public ActionResult Detail_Staff()
        {
            string UserName = Request["USERNAME"];

            if (UserName != null)
            {
                Staff p = StaffTool.FindStaff(UserName);
                if (p != null)
                {
                    return(View(p));
                }
                else
                {
                    return(RedirectToAction("Show_Staff"));
                }
            }
            else
            {
                return(RedirectToAction("Show_Staff"));
            }
        }