public ActionResult LogOn(LogOnModel model, string returnUrl)
        {
            try
            {

//ManageService 中定義了驗證使用者名稱的方法 VerifyUserLogon， 在之前的第四課中寫了如何去驗證使用者名稱密碼
                ManageService _manageService = new ManageService();  
                if (ModelState.IsValid)
                {   

//判斷輸入的使用者名稱密碼是否正確
                    bool _isUserLogon = _manageService.VerifyUserLogOn(model.UserName, model.Password);
                    string role = "Admin";
                    if (_isUserLogon)
                    {
                        FormsAuthenticationTicket authTicket = new FormsAuthenticationTicket(1,   //版本

//將新的Ticket轉變為Cookie值，並新增到Cookies集合中

                        string encTicket = FormsAuthentication.Encrypt(authTicket);
                        this.Response.Cookies.Add(new HttpCookie(FormsAuthentication.FormsCookieName, encTicket));
                        this.Response.Cookies.Add(new HttpCookie("role", role));
                    }
                }
                return RedirectToAction("Index", "Home");

                // If we got this far, something failed, redisplay form
            }
            catch(Exception ex)
            {
                throw new Exception("Log on failed:" + ex.Message);
            }

}