VBA?
Sub VPOn()
Dim objVP As AcadPViewport
Dim objStuff() As AcadEntity
Dim objSSet As AcadSelectionSet
Dim intGrp(0) As Integer
Dim varData(0) As Variant
intGrp(0) = 0
varData(0) = "viewport"
On Error GoTo UhOh
Set objSSet = ThisDrawing.PickfirstSelectionSet
objSSet.Select acSelectionSetAll, , , intGrp, varData
For Each objVP In objSSet
objVP.ViewportOn = True
Next objVP
BuhBye:
Exit Sub
UhOh:
Select Case Err.Number
Case -2145386494
Err.Clear
Resume Next
Case Else
Debug.Print Err.Number
GoTo BuhBye
End Select
End Sub
Sub VPOff()
Dim objVP As AcadPViewport
Dim objStuff() As AcadEntity
Dim objSSet As AcadSelectionSet
Dim intGrp(0) As Integer
Dim varData(0) As Variant
intGrp(0) = 0
varData(0) = "viewport"
On Error GoTo UhOh
Set objSSet = ThisDrawing.PickfirstSelectionSet
objSSet.Select acSelectionSetAll, , , intGrp, varData
For Each objVP In objSSet
objVP.ViewportOn = False
Next objVP
BuhBye:
Exit Sub
UhOh:
Select Case Err.Number
Case -2145386494
Err.Clear
Resume Next
Case Else
Debug.Print Err.Number
GoTo BuhBye
End Select
End Sub