當在asp.net核心1.0中渲染部分視圖時，ViewBag數據不存在

在asp.net核心1.0（Full Framework 4.6.1）中，我需要渲染一個局部視圖到字符串，所以基於https://gist.github.com/ahmad-moussawi/1643d703c11699a6a4046e57247b4d09，我創建的RenderView：當在asp.net核心1.0中渲染部分視圖時，ViewBag數據不存在

public class ViewRender 
{ 
    private IRazorViewEngine _viewEngine; 
    private ITempDataProvider _tempDataProvider; 
    private IServiceProvider _serviceProvider; 

    public ViewRender(
     IRazorViewEngine viewEngine, 
     ITempDataProvider tempDataProvider, 
     IServiceProvider serviceProvider) 
    { 
     _viewEngine = viewEngine; 
     _tempDataProvider = tempDataProvider; 
     _serviceProvider = serviceProvider; 
    } 

    public string Render<TModel>(string view, TModel model) 
    { 
     var actionContext = GetActionContext(); 

     var viewEngineResult = _viewEngine.FindView(actionContext, view, false); 

     if (!viewEngineResult.Success) 
     { 
      throw new InvalidOperationException(string.Format("Couldn't find view '{0}'", view)); 
     } 

     var viewResult = viewEngineResult.View; 

     using (var output = new StringWriter()) 
     { 
      var viewContext = new ViewContext(
       actionContext, 
       viewResult, 
       new ViewDataDictionary<TModel>(
        metadataProvider: new EmptyModelMetadataProvider(), 
        modelState: new ModelStateDictionary()) 
       { 
        Model = model 
       }, 
       new TempDataDictionary(
        actionContext.HttpContext, 
        _tempDataProvider), 
       output, 
       new HtmlHelperOptions()); 

      viewContext.Vi 
      viewResult.RenderAsync(viewContext).GetAwaiter().GetResult(); 

      return output.ToString(); 
     } 
    } 

    private ActionContext GetActionContext() 
    { 
     var httpContext = new DefaultHttpContext(); 
     httpContext.RequestServices = _serviceProvider; 
     return new ActionContext(httpContext, new RouteData(), new ActionDescriptor()); 
    } 
}

然而，當控制器調用PartialView：

string render = _viewRender.Render("Directory/_DirectoryData", directory);

數據集分成ViewBag控制器先前如下。

<label asp-for="DirectoryItem_DirectoryItem" class="form-control-label"></label> 
<select asp-for="DirectoryItem_DirectoryItem" asp-items="@(new SelectList(ViewBag.DirectoryList, "Id", "DirectoryId", null))" class="form-control"> 
    <option>--- Seleccione ---</option> 
</select>

和渲染拋出異常：當使用它們的組合框項目

ViewBag.ParticipantTypesList = _dbInstance.ParticipantTypes; 
ViewBag.DirectoryList = _dbInstance.Directories; 
ViewBag.TaxCategoryList = _dbInstance.TaxCategories;

不存在。請幫助我如何獲取或傳輸ViewBag。

¿我必須使用_viewEngine.FindView（...）或_viewEngine.FindPage（...）？

謝謝

來源

2016-07-26 Aldemar Cuartas Carvajal