Private Function Werktage(Start As Date, Ende As Date) As Integer
 
        Dim dt As Date = DateValue(Start.ToString), c As Integer = 0
        Dim dtend As Date = DateValue(Ende.ToString).AddDays(1)
 
        Do
            Dim wochentag As Integer = Microsoft.VisualBasic.Weekday(dt)
            'Unter Annahme: 1 = Sonntag, 7 = Samstag
            If wochentag > 1 And wochentag < 7 Then
                c += 1
            End If
            dt = dt.AddDays(1)
        Loop While dt < dtend
 
        Return c
    End Function