'Verweise auf PresentationCore und WindowsBase hinzufügen!
 
Private WithEvents Medi As New MediaPlayer
 
Sub StarteTitel(datei As String)
  Medi.Open(New Uri(datei))
End Sub
 
Private Sub Medi_MediaOpened(sender As Object, e As EventArgs) Handles _
  Medi.MediaOpened
  LabelDuration.Text = Medi.NaturalDuration.TimeSpan.ToString("mm':'ss")
End Sub