On Cell Change macro revision

[S_Wish]

Hi there! I have a macro to do something if 1 cell is changed, and I am interesting, how can I prevent the sub below from running if multiple cells are changed at a time (copy an array of values must be prohibited, and I want to have an opportunity to delete data, from A2:end of document) I know that I can create a sub to delete values, after pressing a button for example, but for end-user it can be not so great.

Private Sub Worksheet_Change(ByVal Target As Range)
   Dim CurrentRow As Integer
   Dim NumberOfUnitsPerCase As Integer
   
If Intersect(Target, Me.Range("A:A")) Is Nothing Then Exit Sub
    CurrentRow = Target.Row
    If (Target.Cells.Value = "") Then Exit Sub
    NumberOfUnitsPerCase = 24
    Call CheckScannedBarcode(CurrentRow, NumberOfUnitsPerCase)

End Sub

and the second question: is it possible to put this sub into Workbook so it will be the same for all sheets?
Thanks in advance!
Serhii

 

[S_Wish]

ok, found a way to solve multiple cell selection

    If Target.Cells.Count > 1 Then Exit Sub

.
what about the second?