Function Zeitraum(d1 As Date, d2 As Date) As String
    Dim ts As TimeSpan = d2 - d1 'Differenz
 
    ' Zeitraum mit tatsächlichen Tagen der einzelnen Monate.
    Dim d As Date = d1, x As Date, m As Integer = 0
    Do
      x = d1.AddMonths(m + 1)
      If x > d2 Then Exit Do
      d = x : m += 1
    Loop
    Dim ts2 As TimeSpan = d2 - d
 
    Dim sb As New System.Text.StringBuilder
 
    sb.AppendFormat("Zeitraum: {0:f} - {1:f}", d1, d2)
    sb.AppendLine()
    sb.AppendLine()
    sb.AppendFormat("Länge in Tagen: {0} Tage", ts.Days)
    sb.AppendLine()
    sb.AppendFormat("Länge in Wochen: {0} Wochen und {1} Tage", ts.Days \ 7, _
      ts.Days Mod 7)
    sb.AppendLine()
    sb.AppendLine()
    sb.AppendFormat("Länge: {0} Tage, {1} Stunden und {2} Minuten", ts.Days, _
      ts.Hours, ts.Minutes)
    'oder auch so:
    'sb.AppendFormat("Länge: {0:%d} Tage, {0:%h} Stunden und {0:%m} Minuten", 
    ' ts)
    sb.AppendLine()
    sb.AppendLine()
    sb.AppendLine()
    sb.AppendFormat("Länge des Zeitraums: {0} Monate, {1} Wochen, " _
      & "{2} Tage, {3} Stunden und {4} Minuten", _
      m, ts2.Days \ 7, ts2.Days Mod 7, ts2.Hours, ts2.Minutes)
    Return sb.ToString
  End Function