ASP.NET MVC的SelectList項目與模型綁定

Question

我有接受一個複雜的對象參數，它本身所具有的複雜類型集合屬性的控制器。表單發佈後，模型綁定不起作用於我的損壞屬性（它始終爲空）。如何建立下拉菜單爲我的損失屬性，因此該模型將與所選值填充當HTML表單發送到控制器？

注意，我是新來的ASP.NET MVC，這是預先寫好的代碼，我一直在問調試。

查看模型1：

public class EditInspectionViewModel 
    { 
     public long? InsRefreshSeq { get; set; } 
     public string Inspector { get; set; } 
     public string VIN { get; set; } 
     public string Manufacturer { get; set; } 
     public string Plant { get; set; } 
     public string Model { get; set; } 
     public IEnumerable<DamageViewModel> Damages { get; set; } 

     public IEnumerable<GETAREAResult> AreaFilterOptions { get; set; } 
     public IEnumerable<GETDMGTYPEResult> DamageTypeFilterOptions { get; set; } 
     public IEnumerable<GETSEVERITYResult> SeverityFilterOptions { get; set; } 
     public IEnumerable<GETGRIDResult> GridFilterOptions { get; set; }  
    } 

查看模型2：

public class DamageViewModel 
{ 
    public long DamageId { get; set; } 
    public string Area { get; set; } 
    public string AreaCode { get; set; } 
    public string TypeCode { get; set; } 
    public string SeverityCode { get; set; } 
    public string GridCode { get; set; } 
    public string Type { get; set; } 
    public string Severity { get; set; } 
    public string Grid { get; set; } 
    public bool HasError { get; set; } 
    public bool HasAreaError { get; set; } 
    public bool HasDamageTypeError { get; set; } 
    public bool HasSeverityError { get; set; } 
    public bool HasImages { get; set; }   
} 

控制器編輯方法：

[HttpGet] 
    public virtual ActionResult Edit(long id) 
    { 

      EditInspectionViewModel viewModel = _getInspectionForEditingQuery.Execute(CurrentUserId, id); 
      viewModel.InsRefreshSeq = 0; 
      viewModel.AreaFilterOptions = _refService.GetAreas().OrderBy(x => x.ARECODE); 
      viewModel.DamageTypeFilterOptions = _refService.GetDamageTypes().OrderBy(x => x.DTPCODE); 
      viewModel.SeverityFilterOptions = _refService.GetSeverities().OrderBy(x => x.SEVCODE); 
      viewModel.GridFilterOptions = _refService.GetQuadrants().OrderBy(x => x.QUDCODE); 

     return View(viewModel); 
    } 


[HttpPost] 
    public virtual ActionResult Edit(long id, EditInspectionViewModel editedInspection) 
    { 
     if (ModelState.IsValid) 
     { 
      _updateErrorInspectionCommand.Execute(editedInspection); 

      return View(editedInspection); 
     } 

     return View(editedInspection); 
    } 

這裏是一個顯示檢查損害的局部剃刀視圖（二者此視圖和外視圖被鍵入到EditInspectionViewModel）：

 @model AIM.NewCars.Model.Inspections.EditInspectionViewModel 

    @{ 

    } 

<div class="panel panel-info"> 
    <div class="panel-heading clearfix"> 


    </div> 
    <table class="table table-condensed"> 
     <thead> 
      <tr> 
       <th>Area</th> 
       <th>Type</th> 
       <th>Severity</th> 
       <th>Grid</th> 
       <th>Images</th> 
       <th>Remove</th> 
      </tr> 
     </thead> 
     <tbody> 
      @foreach (var damage in Model.Damages) 
      { 
       if (damage.HasError) 
       { 
        IEnumerable<SelectListItem> areas = Model.AreaFilterOptions.Select(x => new SelectListItem() { Value = x.ARECODE, Text = x.ARECODE + "-" + x.AREDESC, Selected = damage.AreaCode == x.ARECODE }); 
        IEnumerable<SelectListItem> damageTypes = Model.DamageTypeFilterOptions.Select(x => new SelectListItem() { Value = x.DTPCODE, Text = x.DTPCODE + "-" + x.DTPDESC, Selected = damage.TypeCode == x.DTPCODE }); 
        IEnumerable<SelectListItem> severities = Model.SeverityFilterOptions.Select(x => new SelectListItem() { Value = x.SEVCODE, Text = x.SEVCODE + "-" + x.SEVDESC, Selected = damage.SeverityCode == x.SEVCODE }); 
        IEnumerable<SelectListItem> grids = Model.GridFilterOptions.Select(x => new SelectListItem() { Value = x.QUDCODE, Text = x.QUDCODE + "-" + x.QUDDESC, Selected = damage.GridCode == x.QUDCODE }); 

        <tr class="damage-container"> 
         <td> 
          <input type="hidden" name="@("InspectionDamages[" + Model.Index + "].Index")" value="@Model.Index" /> 

          @Html.DropDownList("InspectionDamages[" + damage.DamageId + "].AreaCode", areas, string.Empty, new { @class = "form-control js-damage-field" }) 
         </td> 
         <td> 

          @Html.DropDownList("Damages[" + damage.DamageId + "].DamageTypeCode", damageTypes, string.Empty, new { @class = "form-control js-damage-field" }) 
         </td> 
         <td> 

          @Html.DropDownList("InspectionDamages[" + damage.DamageId + "].SeverityCode", severities, string.Empty, new { @class = "form-control js-damage-field" }) 
         </td> 
         <td> 

          @Html.DropDownList("InspectionDamages[" + damage.DamageId + "].GridCode", grids, string.Empty, new { @class = "form-control js-damage-field" }) 
         </td> 
        } 
     </tbody> 
     </table> 
     </div> 

後的HTTP GET，下拉菜單會根據他們的價值觀就好獲取填充和選擇，但是當我發佈形式的賠償屬性爲null，當它到達後的操作方法。

Answer 1

您的模型綁定不起作用，因爲您的模型以錯誤的方式使用。使用for循環代替foreach並在for循環中使用DropDownListFor適當的DamageViewModel。然後你會得到你所需要的表格模型綁定。請記住，絕對不要試圖通過你自己的代碼來模擬模型綁定，因爲它容易出錯並且很難做出以後的更改，因爲總是有這種可能性。