ExternalCommandsData Properties

Name	Return Type	Description
P AssemblyName	string	The assembly path of the menu item.
P AvailabilityClassName	string	The full class name for the class providing the entry point to decide availability of this menu item.
P ClassName	string	The name of the class containing the implementation for the command.
P IsValidObject	Boolean	Specifies whether the .NET object represents a valid Revit entity.