Context.SaveChanges（）在應用程序重新啓動之前不起作用

Question

我在某些酒店應用程序上工作。我有一個ListView和一些列，一列是CheckBox列。當我點擊該複選框時，所選項目將從ListView中移除。 另外，當我點擊該CheckBox時，我調用WCF服務中的方法，這種方法效果不佳。在數據庫中，我有一個名爲「IsFinished」的布爾列表（tblStay）。點擊CheckBox後，我需要將該列設置爲「True」。現在這很奇怪：在我放置斷點並檢查一切是否正常工作之後，它實際上運行良好。字段「IsFinished」的值爲「True」，但在我的數據庫中它仍然設置爲false。然後我重新啓動應用程序並再次執行相同的操作，然後在我的數據庫中將其保存爲「True」。這並非總是如此。有時會保存正確，但在大多數情況下，它不起作用。這裏是我的代碼：

視圖模型：

private ServiceReference1.tblStayGuest mainGuest; 
    public ServiceReference1.tblStayGuest MainGuest //bound as selected item in ListView 
    { 
     get 
     { 
      return mainGuest; 
     } 
     set 
     { 
      mainGuest = value; 
      OnPropertyChanged("MainGuest"); 
     } 
    } 

private ObservableCollection<ServiceReference1.tblStayGuest> mainGuests; 
    public ObservableCollection<ServiceReference1.tblStayGuest> MainGuests //bound as items source in ListView 
    { 
     get 
     { 
      return mainGuests; 
     } 
     set 
     { 
      mainGuests = value; 
      OnPropertyChanged("MainGuests"); 
     } 
    } 


private ICommand _FinishedStay; // this command is bound to my CheckBox column in listview 
    public ICommand FinishedStay 
    { 
     get 
     { 
      if (_FinishedStay == null) 
      { 
       _FinishedStay = new DelegateCommand(delegate() 
       { 
        try 
        { 
         ServiceReference1.Service1Client wcf = new ServiceReference1.Service1Client(); 
         MainGuest.IsMainGuest = false; 
         wcf.FinishedStay(MainGuest); 

         if (MainGuest.tblStay.IsFinished == true) 
         {         
          MainGuests.Remove(MainGuest); 
         } 
         wcf.Close(); 
        } 
        catch 
        { 
         Trace.WriteLine("working...", "MyApp"); 
        } 
       }); 
      } 
      return _FinishedStay; 
     } 
    } 

WCF：

bool IService1.FinishedStay(tblStayGuest mainGuest) 
    { 
     try 
     { 
      context = new HotelBaseEntities(); 

      //tblStayGuest stGuest = (from stg in context.tblStayGuests where stg.StayGuestID == mainGuest.StayGuestID select stg).FirstOrDefault(); 
      tblStay stay = (from st in context.tblStays where st.StayID == mainGuest.StayID select st).FirstOrDefault(); 
      tblGuest guest = (from g in context.tblGuests where g.GuestID == mainGuest.GuestID select g).FirstOrDefault(); 
      tblBooking book = (from b in context.tblBookings where b.GuestID == mainGuest.GuestID select b).FirstOrDefault(); 
      tblRoom room = (from r in context.tblRooms where r.RoomID == mainGuest.tblStay.RoomID select r).FirstOrDefault(); 


      guest.IsCheckedOut = true; 
      mainGuest.IsMainGuest = false;    
      stay.IsFinished = true; 
      book.IsActive = false; 
      book.IsCanceled = true; 
      room.RoomStatus = false; 
      context.SaveChanges(); 

      var contactEntry = context.ObjectStateManager.GetObjectStateEntry(stay); 
      contactEntry.ChangeState(System.Data.EntityState.Modified); 


      List<tblStayGuest> GuestsInRoom = (from gs in context.tblStayGuests where gs.StayID == mainGuest.StayID select gs).ToList(); 
      foreach (tblStayGuest stayG in GuestsInRoom) 
      { 
       tblGuest guestToCheck = (from gtc in context.tblGuests where gtc.GuestID == stayG.GuestID select gtc).FirstOrDefault(); 
       guestToCheck.IsCheckedOut = true; 
       context.SaveChanges(); 
      } 


      context.SaveChanges(); 
      return true; 
     } 
     catch (Exception e) 
     { 
      e.StackTrace.ToString(); 
      return false; 
     } 
    } 

這究竟是爲什麼？

Answer 1

您是否嘗試過使用context.Entry(stay).State = EntityState.Added;，僅使用一個context.SaveChanges();並在函數外實例化您的環境？