在OrchardCMS v1.8.1.0，我收到内容链接，当点击以下错误消息（/管理/内容/列表）文件的名称模块\ Orchard.MediaLibrary \查看\配件\ Document.SummaryAdmin.cshtml：
你调用的对象是空的。
Source Error:
Line 3: @{
Line 4: DocumentPart documentPart = Model.ContentPart;
//The following line throws the exception
Line 5: var mediaPart = ((ContentItem)Model.ContentItem).As<MediaPart>();
Line 6: }
Line 7:
堆栈跟踪：
[NullReferenceException: Object reference not set to an instance of an object.]
ASP._Page_Modules_Orchard_MediaLibrary_Views_Parts_Document_SummaryAdmin_cshtml.Execute() in c:\inetpub\wwwroot\Modules\Orchard.MediaLibrary\Views\Parts\Document.SummaryAdmin.cshtml:5
System.Web.WebPages.WebPageBase.ExecutePageHierarchy() +279
System.Web.Mvc.WebViewPage.ExecutePageHierarchy() +124
System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage) +124
System.Web.Mvc.Html.PartialExtensions.Partial(HtmlHelper htmlHelper, String partialViewName, Object model, ViewDataDictionary viewData) +146
Orchard.DisplayManagement.Descriptors.ShapeTemplateStrategy.ShapeTemplateBindingStrategy.Render(ShapeDescriptor shapeDescriptor, DisplayContext displayContext, HarvestShapeInfo harvestShapeInfo, HarvestShapeHit harvestShapeHit) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard\DisplayManagement\Descriptors\ShapeTemplateStrategy\ShapeTemplateBindingStrategy.cs:149
Orchard.DisplayManagement.Descriptors.ShapeTemplateStrategy.<>c__DisplayClass28.<Discover>b__15(DisplayContext displayContext) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard\DisplayManagement\Descriptors\ShapeTemplateStrategy\ShapeTemplateBindingStrategy.cs:133
Orchard.DisplayManagement.Descriptors.<>c__DisplayClass5.<BoundAs>b__2(DisplayContext displayContext) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard\DisplayManagement\Descriptors\ShapeAlterationBuilder.cs:56
Orchard.DisplayManagement.Implementation.DefaultDisplayManager.Process(ShapeBinding shapeBinding, IShape shape, DisplayContext context) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard\DisplayManagement\Implementation\DefaultDisplayManager.cs:181
Orchard.DisplayManagement.Implementation.DefaultDisplayManager.Execute(DisplayContext context) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard\DisplayManagement\Implementation\DefaultDisplayManager.cs:94
Orchard.DisplayManagement.Implementation.DisplayHelper.ShapeExecute(Object shape) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard\DisplayManagement\Implementation\DisplayHelper.cs:86
Orchard.DisplayManagement.Implementation.DisplayHelper.TryInvoke(InvokeBinder binder, Object[] args, Object& result) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard\DisplayManagement\Implementation\DisplayHelper.cs:30
CallSite.Target(Closure , CallSite , Object , Object ) +219
Orchard.Core.Shapes.CoreShapes.ContentZone(Object Display, Object Shape, TextWriter Output) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard.Web\Core\Shapes\CoreShapes.cs:274
[TargetInvocationException: Exception has been thrown by the target of an invocation.]
System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor) +0
System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments) +76
System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) +211
Orchard.DisplayManagement.Descriptors.ShapeAttributeStrategy.ShapeAttributeBindingStrategy.PerformInvoke(DisplayContext displayContext, MethodInfo methodInfo, Object serviceInstance) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard\DisplayManagement\Descriptors\ShapeAttributeStrategy\ShapeAttributeBindingStrategy.cs:65
Orchard.DisplayManagement.Descriptors.<>c__DisplayClass5.<BoundAs>b__2(DisplayContext displayContext) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard\DisplayManagement\Descriptors\ShapeAlterationBuilder.cs:56
Orchard.DisplayManagement.Implementation.DefaultDisplayManager.Process(ShapeBinding shapeBinding, IShape shape, DisplayContext context) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard\DisplayManagement\Implementation\DefaultDisplayManager.cs:185
Orchard.DisplayManagement.Implementation.DefaultDisplayManager.Execute(DisplayContext context) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard\DisplayManagement\Implementation\DefaultDisplayManager.cs:94
Orchard.DisplayManagement.Implementation.DisplayHelper.ShapeExecute(Object shape) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard\DisplayManagement\Implementation\DisplayHelper.cs:86
Orchard.DisplayManagement.Implementation.DisplayHelper.TryInvoke(InvokeBinder binder, Object[] args, Object& result) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard\DisplayManagement\Implementation\DisplayHelper.cs:30
CallSite.Target(Closure , CallSite , Object , Object ) +220
ASP._Page_Core_Contents_Views_Content_SummaryAdmin_cshtml.Execute() in c:\inetpub\wwwroot\Core\Contents\Views\Content.SummaryAdmin.cshtml:13
System.Web.WebPages.WebPageBase.ExecutePageHierarchy() +280
System.Web.Mvc.WebViewPage.ExecutePageHierarchy() +125
System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage) +125
System.Web.Mvc.Html.PartialExtensions.Partial(HtmlHelper htmlHelper, String partialViewName, Object model, ViewDataDictionary viewData) +147
Orchard.DisplayManagement.Descriptors.ShapeTemplateStrategy.ShapeTemplateBindingStrategy.Render(ShapeDescriptor shapeDescriptor, DisplayContext displayContext, HarvestShapeInfo harvestShapeInfo, HarvestShapeHit harvestShapeHit) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard\DisplayManagement\Descriptors\ShapeTemplateStrategy\ShapeTemplateBindingStrategy.cs:151
Orchard.DisplayManagement.Descriptors.ShapeTemplateStrategy.<>c__DisplayClass28.<Discover>b__15(DisplayContext displayContext) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard\DisplayManagement\Descriptors\ShapeTemplateStrategy\ShapeTemplateBindingStrategy.cs:133
Orchard.DisplayManagement.Descriptors.<>c__DisplayClass5.<BoundAs>b__2(DisplayContext displayContext) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard\DisplayManagement\Descriptors\ShapeAlterationBuilder.cs:56
Orchard.DisplayManagement.Implementation.DefaultDisplayManager.Process(ShapeBinding shapeBinding, IShape shape, DisplayContext context) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard\DisplayManagement\Implementation\DefaultDisplayManager.cs:185
Orchard.DisplayManagement.Implementation.DefaultDisplayManager.Execute(DisplayContext context) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard\DisplayManagement\Implementation\DefaultDisplayManager.cs:94
Orchard.DisplayManagement.Implementation.DisplayHelper.ShapeExecute(Object shape) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard\DisplayManagement\Implementation\DisplayHelper.cs:86
Orchard.DisplayManagement.Implementation.DisplayHelper.TryInvoke(InvokeBinder binder, Object[] args, Object& result) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard\DisplayManagement\Implementation\DisplayHelper.cs:30
CallSite.Target(Closure , CallSite , Object , Object ) +220
Orchard.Core.Shapes.CoreShapes.List(Object Display, TextWriter Output, IEnumerable`1 Items, String Tag, String Id, IEnumerable`1 Classes, IDictionary`2 Attributes, String ItemTag, IEnumerable`1 ItemClasses, IDictionary`2 ItemAttributes) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard.Web\Core\Shapes\CoreShapes.cs:687
[TargetInvocationException: Exception has been thrown by the target of an invocation.]
System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor) +0
System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments) +76
System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) +211
Orchard.DisplayManagement.Descriptors.ShapeAttributeStrategy.ShapeAttributeBindingStrategy.PerformInvoke(DisplayContext displayContext, MethodInfo methodInfo, Object serviceInstance) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard\DisplayManagement\Descriptors\ShapeAttributeStrategy\ShapeAttributeBindingStrategy.cs:65
Orchard.DisplayManagement.Descriptors.<>c__DisplayClass5.<BoundAs>b__2(DisplayContext displayContext) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard\DisplayManagement\Descriptors\ShapeAlterationBuilder.cs:56
Orchard.DisplayManagement.Implementation.DefaultDisplayManager.Process(ShapeBinding shapeBinding, IShape shape, DisplayContext context) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard\DisplayManagement\Implementation\DefaultDisplayManager.cs:185
Orchard.DisplayManagement.Implementation.DefaultDisplayManager.Execute(DisplayContext context) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard\DisplayManagement\Implementation\DefaultDisplayManager.cs:94
Orchard.DisplayManagement.Implementation.DisplayHelper.ShapeExecute(Object shape) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard\DisplayManagement\Implementation\DisplayHelper.cs:86
Orchard.DisplayManagement.Implementation.DisplayHelper.TryInvoke(InvokeBinder binder, Object[] args, Object& result) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard\DisplayManagement\Implementation\DisplayHelper.cs:30
CallSite.Target(Closure , CallSite , Object , Object ) +220
ASP._Page_Core_Contents_Views_Admin_List_cshtml.Execute() in c:\inetpub\wwwroot\Core\Contents\Views\Admin\List.cshtml:52
System.Web.WebPages.WebPageBase.ExecutePageHierarchy() +280
System.Web.Mvc.WebViewPage.ExecutePageHierarchy() +125
System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage) +125
Orchard.Mvc.ViewEngines.ThemeAwareness.<>c__DisplayClass7.<FindView>b__5(ViewContext viewContext, TextWriter writer, IViewDataContainer viewDataContainer) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard\Mvc\ViewEngines\ThemeAwareness\LayoutAwareViewEngine.cs:60
System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context) +380
System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +109
System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +890
System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +890
System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +890
System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +890
System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +890
System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +890
System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +890
System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +890
System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +890
System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +890
System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +890
System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +890
System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +890
System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList`1 filters, ActionResult actionResult) +97
System.Web.Mvc.Async.<>c__DisplayClass21.<BeginInvokeAction>b__1e(IAsyncResult asyncResult) +241
System.Web.Mvc.Controller.<BeginExecuteCore>b__1d(IAsyncResult asyncResult, ExecuteCoreState innerState) +29
System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +111
System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +53
System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +19
System.Web.Mvc.MvcHandler.<BeginProcessRequest>b__5(IAsyncResult asyncResult, ProcessRequestState innerState) +51
System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +111
Orchard.Mvc.Routes.HttpAsyncHandler.EndProcessRequest(IAsyncResult result) in z:\Builds\work\d1eb156ccc3cb14\src\Orchard\Mvc\Routes\ShellRoute.cs:159
System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +606
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +288
