VS2012 XAML设计器抛出NullReferenceException，但程序仍按预期编译和运行

Question

I have a page that is now showing in the XAML designer as throwing a NullReferenceException , where prior to making a couple of changes it didn't. The changes I made between not seeing the designer error and it appearing were: adding a couple of collapsed checkboxes to a StackPanel and making a couple of elements' visibility bound to their checked status. Additionally, I created handlers for their checked and unchecked events. I have removed these changes (or at least I'm sure I have, but I'm still combing back over it) and the error still persists.

My initial thoughts were that I had declared the checkboxes in the wrong order in the XAML code, but moving these did not remove the error, so I decided tried removing the changes to get it back to how it was pre-error, as noted above. No dice.

What I don't get about it, is the program still compiles fine and behaves exactly as I expected it to after making the changes (and always did). Further, the error being underlined in the XAML text editor is the Page declaration rather than the elements where I was playing around (and including loading the page that is throwing the exception)

I'm quite inexperienced at programming, so I wanted to know; A) is there a method I should be following to track this error down given it's not 'breaking' the compiler and is not throwing an error during debug. B) Given that the program still behaves as expected, how safe is it to continue without rooting out the cause?

(EDITED FROM HERE) Error Message:

NullReferenceException: Object reference not set to an instance of an object.
at PersonalArmyBuilder.WHFB8TH_Upgrader.ResetListBinding()
   at PersonalArmyBuilder.WHFB8TH_Upgrader.rdoItem_Checked(Object sender, RoutedEventArgs e)
   at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
   at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
   at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
   at System.Windows.UIElement.RaiseEvent(RoutedEventArgs e)
   at System.Windows.Controls.RadioButton.OnChecked(RoutedEventArgs e)
   at System.Windows.Controls.Primitives.ToggleButton.OnIsCheckedChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
   at System.Windows.DependencyObject.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
   at System.Windows.FrameworkElement.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
   at System.Windows.DependencyObject.NotifyPropertyChange(DependencyPropertyChangedEventArgs args)
   at System.Windows.DependencyObject.UpdateEffectiveValue(EntryIndex entryIndex, DependencyProperty dp, PropertyMetadata metadata, EffectiveValueEntry oldEntry, EffectiveValueEntry& newEntry, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType)
   at System.Windows.DependencyObject.SetValueCommon(DependencyProperty dp, Object value, PropertyMetadata metadata, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType, Boolean isInternal)
   at System.Windows.DependencyObject.SetValue(DependencyProperty dp, Object value)
   at System.Windows.Controls.Primitives.ToggleButton.set_IsChecked(Nullable`1 value)
   at PersonalArmyBuilder.WHFB8TH_Upgrader.SetRadioButtonInitialStatus()
   at PersonalArmyBuilder.WHFB8TH_Upgrader.UserControl_Loaded(Object sender, RoutedEventArgs e)
   at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
   at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
   at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
   at System.Windows.UIElement.RaiseEvent(RoutedEventArgs e)
   at System.Windows.BroadcastEventHelper.BroadcastEvent(DependencyObject root, RoutedEvent routedEvent)
   at System.Windows.BroadcastEventHelper.BroadcastLoadedEvent(Object root)
   at MS.Internal.LoadedOrUnloadedOperation.DoWork()
   at System.Windows.Media.MediaContext.FireLoadedPendingCallbacks()
   at System.Windows.Media.MediaContext.FireInvokeOnRenderCallbacks()
   at System.Windows.Media.MediaContext.RenderMessageHandlerCore(Object resizedCompositionTarget)
   at System.Windows.Media.MediaContext.RenderMessageHandler(Object resizedCompositionTarget)
   at System.Windows.Media.MediaContext.Resize(ICompositionTarget resizedCompositionTarget)
   at System.Windows.Interop.HwndTarget.OnResize()
   at System.Windows.Interop.HwndTarget.HandleMessage(WindowMessage msg, IntPtr wparam, IntPtr lparam)
   at System.Windows.Interop.HwndSource.HwndTargetFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)

Answer 1

刚刚通过继续执行其他任务发现了问题-事实证明，我试图在用户控件的load事件期间运行一个方法，并且它引用的是尚未实例化的对象。