动态设置Cookies过期时间

DateTime dt = new DateTime;              

  switch (dropSaveDate.SelectedValue)//dropSaveDate为         

       {               

     case "2小时":                        dt = DateTime.Now.AddMinutes(120);//二小时过期                        break;                    case"一天":                        dt = DateTime.Now.AddDays(1);                        break;                 

   case"一周":                        dt = DateTime.Now.AddDays(7);                        break;                   

 case"一月":                        dt = DateTime.Now.AddMonths(1);                        break;         

           default:                        break;            

    }                // 创建身份验证票证               

 FormsAuthenticationTicket authTicket = new FormsAuthenticationTicket

(                                    

          1, // version                                      

gUserId, // user name                                     

  DateTime.Now, // 开始时间                          

   dt,// 过期时间为一   //天:DateTime.Now.AddDays(1)                          

             true, // 持久性，若为True，需设置,Cookies的Expires属性,若为False，则关闭浏览器就会失效                                      

  ""// User data

 );                 

string encryptedTicket = FormsAuthentication.Encrypt(authTicket);                // 创建Cookie    HttpCookie authCookie = new HttpCookie(FormsAuthentication.FormsCookieName, encryptedTicket);   

 authCookie.Expires = authTicket.Expiration;    

 Response.Cookies.Add(authCookie);