Track changes by creating timestamp - vba

Question

The original code (Excel VBA) I found works fine for keeping track of one column:
Private Sub Worksheet_Change(ByVal Target As Range)
'Update 20140722
Dim WorkRng As Range
Dim Rng As Range
Dim xOffsetColumn As Integer
Set WorkRng = Intersect(Application.ActiveSheet.Range("P:P"), Target)
xOffsetColumn = 2
If Not WorkRng Is Nothing Then
Application.EnableEvents = False
For Each Rng In WorkRng
If Not VBA.IsEmpty(Rng.Value) Then
Rng.Offset(0, xOffsetColumn).Value = Date
Rng.Offset(0, xOffsetColumn).NumberFormat = "dd-mm-yyyy"
Else
Rng.Offset(0, xOffsetColumn).ClearContents
End If
Next
Application.EnableEvents = True
End If
End Sub
I want to track two columns. Below, you will find the newly added code. It does not work, even though I changed variable names after the Dim (by adding a b). Simple copy-pasting the old code and then only change the range from P:P to S:S and the xOffsetColumn also does not work.
Private Sub Worksheet_Change_b(ByVal Target As Range)
'Update 20140722
Dim WorkRngb As Range
Dim Rngb As Range
Dim xOffsetColumnb As Integer
Set WorkRngb = Intersect(Application.ActiveSheet.Range("S:S"), Target)
xOffsetColumnb = 3
If Not WorkRngb Is Nothing Then
Application.EnableEvents = False
For Each Rngb In WorkRngb
If Not VBA.IsEmpty(Rngb.Value) Then
Rngb.Offset(0, xOffsetColumnb).Value = Date
Rngb.Offset(0, xOffsetColumnb).NumberFormat = "dd-mm-yyyy"
Else
Rngb.Offset(0, xOffsetColumnb).ClearContents
End If
Next
Application.EnableEvents = True
End If
End Sub

Answer 1

This modification to your original Worksheet_Change event macro should take care of both columns including pasting multiple values into a range that encompasses one or both columns.
Private Sub Worksheet_Change(ByVal Target As Range)
'Update 20150930
If Not Intersect(Target, Union(Columns("P"), Columns("S"))) Is Nothing Then
On Error GoTo bm_Safe_Exit
Application.EnableEvents = False
Dim rng As Range
For Each rng In Intersect(Target, Union(Columns("P"), Columns("S")))
If Not VBA.IsEmpty(rng) Then
rng.Offset(0, 2 - CBool(rng.Column = 19)) = Date
rng.Offset(0, 2 - CBool(rng.Column = 19)).NumberFormat = "dd-mm-yyyy"
Else
rng.Offset(0, 2 - CBool(rng.Column = 19)).ClearContents
End If
Next rng
End If
bm_Safe_Exit:
Application.EnableEvents = True
End Sub
To simply the offset, I simply worked back two columns from column P to column N. I'm not sure why the second event macro sample only moved back to column P; I didn't think it was your intention to overwrite the values in column P.
The Application.ActiveSheet.Range("P:P") column reference was unnecessary and potentially dangerous if the event macro was triggered by code that changed one of the values while another worksheet held the ActiveSheet property. Worksheet code pages are private by default; module code pages are public by default. You can reference cells and ranges without explicitly declaring their parent in a worksheet code sheet while that is bad coding practice on a module code sheet.
I also changed the value used for the timestamp from Date to Now. The cell formatting will still only display the date but if you ever need it, you will have the time as well.