The exception thrown when Revit cancels a background operation. Third-party developers are not expected to catch and handle this exception. Instead, if allowed to propagate back to Revit code, it will be handled by Revit.

[SerializableAttribute]
public class BackgroundTaskCancelledException : ApplicationException

<SerializableAttribute> _
Public Class BackgroundTaskCancelledException _
	Inherits ApplicationException

[SerializableAttribute]
public ref class BackgroundTaskCancelledException : public ApplicationException