https://learn.microsoft.com/fr-fr/dotnet/api/system.windows.markup.xamlsettypeconvertereventargs?view=netframework-4.8.1&viewFallbackFrom=windowsdesktop-9.0
XamlSetTypeConverterEventArgs Class (System.Windows.Markup) | Microsoft Learn
Provides data for callbacks that are invoked when a XAML writer sets a value using a type converter call.
class systemwindowsmarkupmicrosoftlearn