/// <summary>
 /// Checks whether there are valid stations selected for the arrival and departure.
 /// </summary>
 /// <returns>Returns true, if the selections are valid. Otherwise false.</returns>
 private bool AreValidConnectionStationsSelected() =>
 ComboboxValidater.ContainValidLocations(this.cbArrival, this.cbDeparture);
 /// <summary>
 /// Checks whether a valid station board station is selected.
 /// </summary>
 /// <returns>True, if there is a valid statio board station selected. Otherwise false.</returns>
 private bool IsValidStationBoardStation() =>
 ComboboxValidater.ContainValidLocations(this.cbSearchStationBoard);