解决cookie的Expires属性值总是0001-1-1 0:00:00的问题

给cookie的Expires赋值，发现读出值都是0001-1-1 0:00:00；跟踪调试发现不是转换问题，cookie读取后默认值就是0001-1-1 0:00:00。解决方法，设置过期项目：

 

HttpCookie cookie  =  System.Web.HttpContext.Current.Request.Cookies[ " User " ];
         if  (cookie  !=   null )
         {
            cookie["UserName"] = _actors.ActorTitle;
            cookie["UserID"] = _actors.ActorID.ToString();
            cookie["DateTime"] = DateTime.Now.AddDays(30).ToString();
            System.Web.HttpContext.Current.Response.SetCookie(cookie);
        }
         else
         {
            cookie = new HttpCookie("User");
            cookie.Values.Add("UserName", _actors.ActorTitle);
            cookie.Values.Add("UserID", _actors.ActorID.ToString());
            cookie.Values.Add("DateTime", DateTime.Now.AddDays(30).ToString());
            System.Web.HttpContext.Current.Response.AppendCookie(cookie);
        }