Ciao folal !
Potresti usare questa funzione:
codice:
Option Explicit
'-------------------------
Public Function CtrDig(KeyAscii As Integer) As Integer
If Not IsNumeric(Chr(KeyAscii)) Then
    KeyAscii = 0
End If
    CtrDig = KeyAscii
End Function
'-------------------------
Private Sub Text1_KeyPress(KeyAscii As Integer)
KeyAscii = CtrDig(KeyAscii)
End Sub