https://docs.microsoft.com/en-us/aspnet/mvc/overview/getting-started/getting-started-with-ef-using-mvc/sorting-filtering-and-paging-with-the-entity-framework-in-an-asp-net-mvc-applicationpublic ActionResult Index(string sortOrder){   ViewBag.NameSortParm = String.IsNullOrEmpty(sortOrder) ? "name_desc" : "";   ViewBag.DateSortParm = sortOrder == "Date" ? "date_desc" : "Date";   var students = from s in db.Students                  select s;   switch (sortOrder)   {      case "name_desc":         students = students.OrderByDescending(s => s.LastName);         break;      case "Date":         students = students.OrderBy(s => s.EnrollmentDate);         break;      case "date_desc":         students = students.OrderByDescending(s => s.EnrollmentDate);         break;      default:         students = students.OrderBy(s => s.LastName);         break;   }   return View(students.ToList());}三元運(yùn)算符僅根據(jù)條件返回結(jié)果之一，它們不會(huì)更改 sortOrder 對(duì)嗎？如果 sortOrder 是“Date”，那么代碼將設(shè)置ViewBag.DateSortParm 為“date_desc”，但 sortOrder 不是仍然是“Date”，所以它實(shí)際上不會(huì)改變順序？我看不出這段代碼如何正常工作，但確實(shí)如此。