https://learn.microsoft.com/en-us/dotnet/api/system.windows.documents.serialization.writingcancelledeventargs?view=netframework-4.8.1&viewFallbackFrom=windowsdesktop-10.0
WritingCancelledEventArgs Class (System.Windows.Documents.Serialization) | Microsoft Learn
Provides data for the WritingCancelled event.
class systemwindowsdocumentsserializationmicrosoft