Vc pode fazer assim....é mó gambi
Dim Vnum As Integer 'Declara no general
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Private Sub Form_Load() 'no form load
Vnum = 0
End Sub
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Private Sub Text1_KeyPress(KeyAscii As Integer) 'na propriedade KeyPress do text
If KeyAscii = 44 Then
If Vnum = 1 Then
KeyAscii = 0
Else
Vnum = 1
End If
End If
End Sub
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Acho que quebra o galho....
Abraço