loginout
FormsAuthentication.SignOut();
HttpContext.Current.Session.RemoveAll();
FormsAuthenticationTicket ticket = new FormsAuthenticationTicket(1, id, DateTime.Now, DateTime.Now.AddHours(1), false, FormsAuthentication.FormsCookiePath);
string encryptTicket = FormsAuthentication.Encrypt(ticket);
HttpCookie authCookie = new HttpCookie(FormsAuthentication.FormsCookieName, encryptTicket); //session timeout為180分鐘
authCookie.Expires = DateTime.Now.AddHours(1);
HttpContext.Current.Response.Cookies.Add(authCookie);
HttpContext.Current.Session["login"] = customVM;
