Oppure:

codice:
      Try
  
            For Each c As Control In Me.Controls
                If TypeOf (c) Is TextBox Then
                    If c.Text <> "" Then
                        ' la azione che preferisci
                        Debug.Print(c.Text) 'x eventuale controllo
                    End If
                End If
            Next

        Catch ex As Exception
            Debug.Print(ex.ToString)
        End Try