模型狀態無效：當我有dropdownlists時如何返回查看？

Question

我有超過40個領域的大視野。其中一些字段是下拉列表，我使用selectlistitems列表填充。

我使用我的視圖模型的註釋，使他們中的一些要求。

現在，我想使ModelState.IsValid檢查，並返回到出現問題的獨到見解，如果有一些錯誤。

問題是，如果我只是簡單地創建一個return View(model)，我所有的下拉列表都會使網站崩潰，因爲它們需要再次填充才能加載頁面。

所以我的問題是：如何處理返回時的ModelState是無效的。

我的控制器：

public ActionResult CreateSelling(SellingAdViewModel model) 
    { 
     if (ModelState.IsValid) 
     { 
      SellingAdvert sellingAdvert = setSellingAd(model); 

      var stored_advert = sellingAdvertService.Create(sellingAdvert); 



      if (User != null && User.Identity.IsAuthenticated) 
      { 
       if (model.AcceptPartner) 
       { 
        notifyPartner(stored_advert); 
       } 

       return RedirectToAction("Upgrade", "Ads", new { AdvertID = stored_advert.Id }); 
      } 
      else 
      { 
       return RedirectToAction("ActivateAnonymous", "Ads", new { AdvertID = stored_advert.Id, anonymousId = model.UserId, AdvertType = "selling" }); 
      } 
     } 

     return View(model); 
    } 

我的視圖模型（我有一個從這個派生的SellingAdViewModel並添加更多的特性）：

public class BasicAdViewModel 
{ 
    public int SectorId { get; set; } 
    public Guid UserId { get; set; } 
    public bool IsAnonymousUser { get; set; } 
    public int AdvertId { get; set; } 

    [DisplayName("Titel:")] 
    [Required(ErrorMessage = "Titel skal udfyldes")] 

    public string Headline { get; set; } 

    [DisplayName("Beskrivelse:")] 
    [StringLength(50, ErrorMessage = "Beskrivelsen minimum fylde 50 karakterer")] 
    public string Description { get; set; } 

    [DisplayName("Søgeord:")] 
    public string SearchWords { get; set; } 


    [DisplayName("Undertitel:")] 
    public string Subtitle { get; set; } 

    [DisplayName("Type af drift")] 
    public List<SelectListItem> OperationTypes { get; set; } 

    [Required] 
    public int SelectedOperationTypeId { get; set; } 


    [Required] 
    public int SelectedSectorId { get; set; } 
    public IEnumerable<GroupedSelectListItem> Sectors { get; set; } 
} 

設置我dropdownlists擺在首位：

我的模型有List<SelectListItem> p roperties，我填充它們具有幾個輔助方法：

SellingAdViewModel model = new SellingAdViewModel() 
      { 
       BusinessEntityTypes = ModelListHelpers.GetBusinessEntityTypes(), 
       FoundedYears = ModelListHelpers.GetFoundedYears(null), 
       ReasonForSale = ModelListHelpers.GetReasonForSale(), 
       RevenuePrediction = ModelListHelpers.GetRevenuePrediction(), 
       RevenueStatus = ModelListHelpers.GetRevenueStatus(), 
       OperationTypes = ModelListHelpers.GetOperationTypes(), 
       Region = ModelListHelpers.GetRegions(), 
       Turnover = ModelListHelpers.Turnovers(), 
       OperatingIn = ModelListHelpers.OperatingIn(), 
       AmountOfEmployees = ModelListHelpers.GetAmountOfEmployees() 
      }; 

Answer 1

我建議你這個解決方案置於TempData模型的GET操作過程中如果模型狀態是無效的，你作出這樣

分配

public ActionResult CreateSelling(SellingAdViewModel model) 
{ 
    if (ModelState.IsValid) 
    { 
     SellingAdvert sellingAdvert = setSellingAd(model); 

     var stored_advert = sellingAdvertService.Create(sellingAdvert); 



     if (User != null && User.Identity.IsAuthenticated) 
     { 
      if (model.AcceptPartner) 
      { 
       notifyPartner(stored_advert); 
      } 

      return RedirectToAction("Upgrade", "Ads", new { AdvertID = stored_advert.Id }); 
     } 
     else 
     { 
      return RedirectToAction("ActivateAnonymous", "Ads", new { AdvertID = stored_advert.Id, anonymousId = model.UserId, AdvertType = "selling" }); 
     } 
    } 

    model.YourList = TempData.Peek("YourList"); 
    return View(model); 
}