CompletionWindow crash NullReferenceException

[PerfectlyFineCode]

AvaloniaEdit version: 0.10.12.2
Avalonia version: 0.10.18
Runtime version: .NET 7.0

Crashes with exceptions

Null Reference Exception

System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation.
 ---> System.NullReferenceException: Object reference not set to an instance of an object.
   at AvaloniaEdit.CodeCompletion.CompletionList.SelectItemFiltering(String query)
   at AvaloniaEdit.CodeCompletion.CompletionList.SelectItem(String text)
   at AvaloniaEdit.CodeCompletion.CompletionWindow.CaretPositionChanged(Object sender, EventArgs e)
   at AvaloniaEdit.Editing.Caret.OnDocumentUpdateFinished()
   at AvaloniaEdit.Editing.TextArea.OnUpdateFinished(Object sender, EventArgs e)
   at InvokeStub_EventHandler.Invoke(Object, Object, IntPtr*)
   at System.Reflection.MethodInvoker.Invoke(Object obj, IntPtr* args, BindingFlags invokeAttr)
   --- End of inner exception stack trace ---
   at System.Reflection.MethodInvoker.Invoke(Object obj, IntPtr* args, BindingFlags invokeAttr)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at System.Delegate.DynamicInvokeImpl(Object[] args)
   at System.Delegate.DynamicInvoke(Object[] args)
   at AvaloniaEdit.Utils.WeakEventManagerBase`4.WeakHandlerList.DeliverEvent(Object sender, TEventArgs args)
   at AvaloniaEdit.Utils.WeakEventManagerBase`4.PrivateDeliverEvent(Object sender, TEventArgs args)
   at AvaloniaEdit.Utils.WeakEventManagerBase`4.DeliverEvent(Object sender, TEventArgs args)
   at AvaloniaEdit.Document.TextDocument.EndUpdate()
   at AvaloniaEdit.Document.TextDocument.Replace(Int32 offset, Int32 length, ITextSource text, OffsetChangeMap offsetChangeMap)
   at AvaloniaEdit.Document.TextDocument.Insert(Int32 offset, String text)
   at AvaloniaEdit.Editing.EmptySelection.ReplaceSelectionWithText(String newText)
   at AvaloniaEdit.Editing.TextArea.ReplaceSelectionWithText(String newText)
   at AvaloniaEdit.Editing.TextArea.PerformTextInput(TextInputEventArgs e)
   at AvaloniaEdit.Editing.TextArea.OnTextInput(TextInputEventArgs e)
   at Avalonia.Input.InputElement.<>c.<.cctor>b__32_4(InputElement x, TextInputEventArgs e) in /_/src/Avalonia.Input/InputElement.cs:line 218
   at Avalonia.Interactivity.RoutedEvent`1.<>c__DisplayClass2_0`1.<AddClassHandler>g__Adapter|0(Object sender, RoutedEventArgs e) in /_/src/Avalonia.Interactivity/RoutedEvent.cs:line 143
   at Avalonia.Interactivity.RoutedEvent.<>c__DisplayClass23_0.<AddClassHandler>b__0(ValueTuple`2 args) in /_/src/Avalonia.Interactivity/RoutedEvent.cs:line 92
   at System.Reactive.AnonymousObserver`1.OnNextCore(T value) in /_/Rx.NET/Source/src/System.Reactive/AnonymousObserver.cs:line 67
   at System.Reactive.ObserverBase`1.OnNext(T value) in /_/Rx.NET/Source/src/System.Reactive/ObserverBase.cs:line 34
   at System.Reactive.Subjects.Subject`1.OnNext(T value) in /_/Rx.NET/Source/src/System.Reactive/Subjects/Subject.cs:line 147
   at Avalonia.Interactivity.RoutedEvent.InvokeRaised(Object sender, RoutedEventArgs e) in /_/src/Avalonia.Interactivity/RoutedEvent.cs:line 99
   at Avalonia.Interactivity.EventRoute.RaiseEventImpl(RoutedEventArgs e) in /_/src/Avalonia.Interactivity/EventRoute.cs:line 148
   at Avalonia.Interactivity.EventRoute.RaiseEvent(IInteractive source, RoutedEventArgs e) in /_/src/Avalonia.Interactivity/EventRoute.cs:line 101
   at Avalonia.Interactivity.Interactive.RaiseEvent(RoutedEventArgs e) in /_/src/Avalonia.Interactivity/Interactive.cs:line 122
   at Avalonia.Input.KeyboardDevice.ProcessRawEvent(RawInputEventArgs e) in /_/src/Avalonia.Input/KeyboardDevice.cs:line 264
   at Avalonia.Input.InputManager.ProcessInput(RawInputEventArgs e) in /_/src/Avalonia.Input/InputManager.cs:line 35
   at Avalonia.Controls.TopLevel.HandleInput(RawInputEventArgs e) in /_/src/Avalonia.Controls/TopLevel.cs:line 508
   at Avalonia.Win32.WindowImpl.AppWndProc(IntPtr hWnd, UInt32 msg, IntPtr wParam, IntPtr lParam) in /_/src/Windows/Avalonia.Win32/WindowImpl.AppWndProc.cs:line 520
   at Avalonia.Win32.WindowImpl.WndProc(IntPtr hWnd, UInt32 msg, IntPtr wParam, IntPtr lParam) in /_/src/Windows/Avalonia.Win32/WindowImpl.WndProc.cs:line 30
   at Avalonia.Win32.Interop.UnmanagedMethods.DispatchMessage(MSG& lpmsg)
   at Avalonia.Win32.Win32Platform.RunLoop(CancellationToken cancellationToken) in /_/src/Windows/Avalonia.Win32/Win32Platform.cs:line 210
   at Avalonia.Threading.Dispatcher.MainLoop(CancellationToken cancellationToken) in /_/src/Avalonia.Base/Threading/Dispatcher.cs:line 65
   at Avalonia.Controls.ApplicationLifetimes.ClassicDesktopStyleApplicationLifetime.Start(String[] args) in /_/src/Avalonia.Controls/ApplicationLifetimes/ClassicDesktopStyleApplicationLifetime.cs:line 120
   at Avalonia.ClassicDesktopStyleApplicationLifetimeExtensions.StartWithClassicDesktopLifetime[T](T builder, String[] args, ShutdownMode shutdownMode) in /_/src/Avalonia.Controls/ApplicationLifetimes/ClassicDesktopStyleApplicationLifetime.cs:line 209
   at AvaloniaTest.Program.Main(String[] args) in D:\Coding\Softwares\Avalonia\AvaloniaTest\Avaloniatest\Program.cs:line 13

I am using this example
http://avalonedit.net/documentation/html/47c58b63-f30c-4290-a2f2-881d21227446.htm

With TextMateSharp.Grammars and Avalonia.TextMate

it seems to crash upon creating a new instance of CompletionWindow
example:

CompletionWindow _completionWindow = new CompletionWindow(_textEditor.TextArea);

I've done debugging and I've double-checked that _textEditor.TextArea does not return null, and it does not return null

[jhimes144]

I'm also experiencing this issue.

The problem is caused by lines 243 - 244 of CompletionList.cs. ApplyTemplate() does not result in OnApplyTemplate getting called every time. Seems like an upstream issue.

if (_listBox == null) ApplyTemplate();