Private Sub Verbrauch_InnerhalbderEingabeDaten()
        Dim interval_days As Integer
        For Zeile As Integer = 0 To DGVStrom.Rows.Count - 2
            'Daten einer Zeilenpaarung in Variablen eintragen
            Dim d1 As Date = DGVStrom.Rows(Zeile).Cells(1).Value
            Dim d2 As Date = DGVStrom.Rows(Zeile + 1).Cells(1).Value
            'aktuelles Ableseintervall in Tagen
            interval_days = (d2 - d1).TotalDays
            If Zeile = 0 Then
                DGVStrom.Rows(Zeile).Cells(6).Value = 0
                DGVStrom.Rows(Zeile + 1).Cells(6).Value = String.Format( _
                  "{0:00}", interval_days)
            Else
                'aktuelles Ableseintervall in Tagen
                DGVStrom.Rows(Zeile + 1).Cells(6).Value = String.Format( _
                  "{0:00}", interval_days)
            End If
        Next Zeile
 
    End Sub