Bonjour,
il suffit de tester si les Textboxes ne sont pas vides:
If Me.txtdate <> "" Then ActiveCell.Offset(0, 2) = CDate(Me.txtdate)
ActiveCell.Offset(0, 3) = Me.txtn_carte
ActiveCell.Offset(0, 4) = Me.cboformation
If Me.txtdateformation <> "" Then ActiveCell.Offset(0, 5) = CDate(Me.txtdateformation)
If Me.cbocotisation <> "" Then ActiveCell.Offset(0, 6) = CDbl(Me.cbocotisation)
Cdlt