Private Sub Berechnen()
 
        iRestzeit = iBasiszeit
 
        Dim dtBeginn As DateTime = Nothing
        Dim dtEnde As DateTime = Nothing
        Dim iDauer As Integer = 0
 
        For Each r As DataRow In dt.Rows
            dtBeginn = r("Beginn")
            dtEnde = r("Ende")
            iDauer = DateDiff(DateInterval.Minute, dtBeginn, dtEnde)
            r("Dauer") = iDauer
            iRestzeit = iRestzeit - iDauer
            r("Restzeit") = iRestzeit
        Next
 
    End Sub