private void OnTravelExpenseItemsSelectionChanged(object obj)
 {
     Telerik.Windows.Controls.SelectionChangeEventArgs e = obj as Telerik.Windows.Controls.SelectionChangeEventArgs;
     if (e == null)
     {
         return;
     }
     foreach (TravelExpense item in e.RemovedItems)
     {
         SelectedTravelExpenses.Remove(item);
     }
     foreach (TravelExpense item in e.AddedItems)
     {
         SelectedTravelExpenses.Add(item);
     }
 }
        public override void OnNavigatedTo(NavigationContext navigationContext)
        {
            base.OnNavigatedTo(navigationContext);
            SelectedTravelExpenses.Clear();

            // Read TravelExpenses
            travelExpenses = new ObservableCollection <TravelExpense>(dbAccess.GetAllTravelExpenses());


            ListOfTravelExpenses = CollectionViewSource.GetDefaultView(travelExpenses);

            ListOfTravelExpenses.CurrentChanged -= ListOfTravelExpenses_CurrentChanged;
            ListOfTravelExpenses.CurrentChanged += ListOfTravelExpenses_CurrentChanged;
            RaisePropertyChanged("ListOfTravelExpenses");
            if (travelExpenses.Count > 0)
            {
                selectedItem = travelExpenses[0];
            }
        }