//Konstruktor for Edit
public WindowReservation(WindowVerwaltung wf, Reservation res)
{
this.DataContext = this;
InitializeComponent();
Title.Content = "Edit Reservation";
CurrentReservation = res;
var ro = new entitiesDataContext().TblRoom.ToList();
cbRoom.ItemsSource = new ObservableCollection <TblRoom>(ro);
cbRoom.SelectedItem = ro.Where <TblRoom>(r => r.RoomId == res.RoomFK).FirstOrDefault();
WF = wf;
}
