public static bool IsExternalFileReference(
	Document aDoc,
	ElementId elemId
)

Public Shared Function IsExternalFileReference ( _
	aDoc As Document, _
	elemId As ElementId _
) As Boolean

public:
static bool IsExternalFileReference(
	Document^ aDoc, 
	ElementId^ elemId
)

Return Value

CAD imports are not external file references, as their data is brought fully into Revit. No connection is maintained to the original file.

A link may be an external resource without being an external file.