https://learn.microsoft.com/ru-ru/dotnet/api/system.xaml.xamlexception?view=netframework-4.8.1&viewFallbackFrom=windowsdesktop-10.0
XamlException Class (System.Xaml) | Microsoft Learn
The exception that is thrown for a general XAML reader or XAML writer exception.
class systemxamlmicrosoftlearn