alphabet incremental counter function

[paccatore]

No problem, the code128 seems to work...
now I'm trying to call this GetNext function from another one that update the value (UltimoSegnacollo) in the table (Postazione), here the code:

Option Compare Database

Function aggiorna_IDcollo()
  
    Dim strQuery2, IDc As String
    Dim db As DAO.Database
    Set db = CurrentDb
       
    strQuery2 = "UPDATE Postazione SET UltimoSegnacollo = " & GetNext((UltimoSegnacollo))
    db.Execute strQuery2, dbFailOnError

Set strQuery2 = Nothing
Set db = Nothing

End Function

but It returns runtime error n°5 on this line:

aryX(3) = IIf(aryX(3) = "Z", 0, Chr(Asc(aryX(3)) + 1))

I've no idea where's the mistake... If I link this function to a button click it works properly eg. AlphaTextField=GetNext(AlphaTextField)

Sorry for the duplicates...

[June7]

Why do you have double () in the function call? Where is aggiorna_IDcollo function? Where is it called from? It could be a Sub instead. Where is UltimoSegnacollo? Why are you using an UPDATE action? This UPDATE will change the UltimoSegnacollo value for every record in the table and I think all will be same value.

How can this (AlphaTextField=GetNext(AlphaTextField)) work? You would be replacing an existing value with the new value. If AlphaTextField is a field in table then you are changing the data in record.

[paccatore]

I'm sorry for the lack... In the meaning I bypassed my issue calling that code by a refresh query and it works.
But now I don't know why this part of my function doesn't works. In facts if I add the SET instruction on the line n° x I got "compilation error, object necessary", not whit pos9 = TBpstz.Fields("PosizioneNove")...

Option Compare Database
Option Explicit

Public Function moltiplicaRG()

'imposta le variabili db (database), rst(tab sorgente), rst_new(tab destinazione), num (numeratore intero)
Dim db As DAO.Database
Set db = CurrentDb
Dim TBpstz As DAO.Recordset
Dim rst, rst_new As DAO.Recordset
Dim num As Integer, IDc As String
Dim codcli, pos9 As String

Set rst = db.OpenRecordset("SELECT * FROM Selezione", , dbOpenSnapshot)
Set rst_new = db.OpenRecordset("RigheGenerate", dbOpenDynaset)
Set TBpstz = db.OpenRecordset("SELECT * FROM Postazione", dbOpenDynaset)
Set codcli = TBpstz.Fields("CodiceIdentificativoCliente")
Set pos9 = TBpstz.Fields("PosizioneNove")                                   ' < THIS IS THE X LINE WHERE DEBUG STOPS, THE NAME OF FIELD IS CORRECT! WHY VBA DOESN'T ACCEPTS "SET" THIS TIME?

'verifica se il contatore dei colli si è esaurito
If TBpstz("UltimoSegnacollo") = "Z999" Then
MsgBox "Questa postazione SDA è satura." & vbCrLf & "Sovrascrivere i dati nella prossima finestra con quelli  della nuova postazione fornita da SDA."
    DoCmd.OpenTable "Postazione"
    
Else

'imposta le condizioni del loop
While Not rst.EOF
For num = 0 To rst.Colli - 1

'imposta le azioni da intraprendere
IDc = TBpstz.Fields("UltimoSegnacollo")
    
'aggiorna UltimoSegnacollo su Postazione
DoCmd.SetWarnings False
    DoCmd.OpenQuery ("013: Aggiorna UltimoSegnacollo su Postazione")
DoCmd.SetWarnings True

    'accoda alla tabella righe generate
rst_new.AddNew
rst_new!NumeroDocumento = rst!NumeroDocumento
rst_new!DataDocumento = rst!DataDocumento
rst_new!Collo = num + 1
rst_new!Colli = rst!Colli
rst_new!Destinatario = rst!Destinatario
rst_new!Indirizzo = rst!Indirizzo
rst_new!CAP = rst!CAP
rst_new!Localita = rst!Localita
rst_new!Provincia = rst!Provincia
rst_new!PesoLordo = rst!PesoLordo
rst_new!LDV = rst!LDV
rst_new!CodPorto = rst!CodPorto
rst_new!Note = rst!Note
rst_new!ImportoAssicurazione = rst!ImportoAssicurazione
rst_new!CodServizio = rst!CodServizio
rst_new!TipoServizio = rst!TipoServizio
rst_new!IDcollo = Right(codcli, 4) & IDc & pos9 & rst!LDV
rst_new.Update
Next
rst.MoveNext
Wend

'chiude gli oggetti e azzera le variabili
TBpstz.Close
rst.Close
rst_new.Close
db.Close

End If
End Function

[June7]

Set is to set an object, not populate a simple string variable.

Just:

pos9 = TBpstz.Fields("PosizioneNove")