Using Programming Languages other than VBA

Sub Example_XRefLayerVisibility()
	' This example reads and modifies the preference value that controls
	' the visibility of xref-dependent layers and specifies if nested xref
	' path changes are saved.
	'
	' When finished, this example resets the preference value back to
	' its original value.

	Dim ACADPref As AcadDatabasePreferences
	Dim originalValue As Variant, newValue As Variant

	' Get the user preferences object
	Set ACADPref = ThisDrawing.preferences

	' Read and display the original value
	originalValue = ACADPref.XRefLayerVisibility
	MsgBox "The XRefLayerVisibility preference is set to: " & originalValue

	' Modify the XRefLayerVisibility preference by toggling the value
	ACADPref.XRefLayerVisibility = Not (ACADPref.XRefLayerVisibility)
	newValue = ACADPref.XRefLayerVisibility
	MsgBox "The XRefLayerVisibility preference has been set to: " & newValue

	' Reset the preference back to its original value
	'
	' * Note: Comment out this last section to leave the change to
	'		 this preference in effect
	ACADPref.XRefLayerVisibility = originalValue
	MsgBox "The XRefLayerVisibility preference was reset back to: " & originalValue
End Sub