Versione 0.2... :bubu: :tongue:

Funziona!!!

codice:
Function contalinee(NomeFile As String) As Long
contalinee = 1
Dim Pos As Long, File As String, Res As Long

'Inserisce il contenuto del file in una variabile
Open NomeFile For Binary As #1
File = Space(LOF(1))
Get #1, 1, File
Close #1

Pos = 1
'In C sarebbe tutto + semplice
prossimo:
Res = InStr(Pos, File, vbNewLine)
If Res = 0 Then
    File = ""
    Exit Function
Else
    contalinee = contalinee + 1
    Pos = Res + 1
End If
GoTo prossimo
End Function
Ciauz!