TargetInvocationException: 调用的目标发生了异常。 StackTrace: 在 System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor) 在 System.Reflection.RuntimeConstructorInfo.Invoke(BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) 在 LuzcDoc.MainViewModel.DoNavChanged(Object obj) 在 LuzcDoc.ZhuWindows.Windowzhu_Loaded(Object sender, RoutedEventArgs e) 在 System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised) 在 System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args) 在 System.Windows.BroadcastEventHelper.BroadcastEvent(DependencyObject root, RoutedEvent routedEvent) 在 System.Windows.BroadcastEventHelper.BroadcastLoadedEvent(Object root) 在 MS.Internal.LoadedOrUnloadedOperation.DoWork() 在 System.Windows.Media.MediaContext.FireLoadedPendingCallbacks() 在 System.Windows.Media.MediaContext.FireInvokeOnRenderCallbacks() 在 System.Windows.Media.MediaContext.RenderMessageHandlerCore(Object resizedCompositionTarget) 在 System.Windows.Media.MediaContext.RenderMessageHandler(Object resizedCompositionTarget) 在 System.Windows.Interop.HwndTarget.OnResize() 在 System.Windows.Interop.HwndTarget.HandleMessage(WindowMessage msg, IntPtr wparam, IntPtr lparam) 在 System.Windows.Interop.HwndSource.HwndTargetFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled) 在 MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled) 在 MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o) 在 System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs) 在 System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler) NullReferenceException: 未将对象引用设置到对象的实例。 StackTrace: 在 LuzcDoc.luzc导出.page.Grid_Initialized(Object sender, EventArgs e) 在 System.Windows.FrameworkElement.RaiseInitialized(EventPrivateKey key, EventArgs e) 在 System.Windows.FrameworkElement.TryFireInitialized() 在 MS.Internal.Xaml.Runtime.ClrObjectRuntime.InitializationGuard(XamlType xamlType, Object obj, Boolean begin) 在 System.Xaml.XamlObjectWriter.Logic_EndInit(ObjectWriterContext ctx) 在 System.Xaml.XamlObjectWriter.WriteEndObject() 在 System.Windows.Markup.WpfXamlLoader.TransformNodes(XamlReader xamlReader, XamlObjectWriter xamlWriter, Boolean onlyLoadOneNode, Boolean skipJournaledProperties, Boolean shouldPassLineNumberInfo, IXamlLineInfo xamlLineInfo, IXamlLineInfoConsumer xamlLineInfoConsumer, XamlContextStack`1 stack, IStyleConnector styleConnector) 在 System.Windows.Markup.WpfXamlLoader.Load(XamlReader xamlReader, IXamlObjectWriterFactory writerFactory, Boolean skipJournaledProperties, Object rootObject, XamlObjectWriterSettings settings, Uri baseUri) 在 System.Windows.Markup.WpfXamlLoader.LoadBaml(XamlReader xamlReader, Boolean skipJournaledProperties, Object rootObject, XamlAccessLevel accessLevel, Uri baseUri) 在 System.Windows.Markup.XamlReader.LoadBaml(Stream stream, ParserContext parserContext, Object parent, Boolean closeStream) 在 LuzcDoc.luzc导出.page..ctor()