private void ListBoxSelectionChanged(object sender, SelectionChangedEventArgs e) { if (lstMissions.Items.Count <= 0) { return; } if (((MissionDto)lstMissions.SelectedItem).Mission.Id == 0) { _missionObjectViewSource.Source = new List <MissionObjectDto>(); return; } _normWs.MissionObjectServiceGetAllMissionObjectsForMissionsCompleted += this.WsMissionObjectServiceGetAllMissionObjectsForMissionsCompleted; _normWs.MissionObjectServiceGetAllMissionObjectsForMissionsAsync(new[] { ((MissionDto)lstMissions.SelectedItem).Mission }); }