WPF

<Grid>
  <Grid.ColumnDefinitions>
    <ColumnDefinition Width="1*" />
    <ColumnDefinition Width="40" />
    <ColumnDefinition Width="1*" />
  </Grid.ColumnDefinitions>
  <ListBox Grid.Column="0" Name="supply" HorizontalAlignment="Stretch" />
  <!-- buttons -->
  <ListBox Grid.Column="2" Name="select" HorizontalAlignment="Stretch" />
</Grid>

public void LoadDirective()
        {
            //DerivedAttributeEntity oDAEEntity;
            listdata = new ObservableCollection<DADirective>();            
            SelectDirective = (DADirective)lbDirectiveList.SelectedItem;

            listdata.Add(new DADirective { DirectiveName = "Filter trading account", DirectiveDescription = "Rows will Trading account value to be filtered" });
            listdata.Add(new DADirective { DirectiveName = "Filter Counter party rows", DirectiveDescription = "Rows where counter party is null will be filtered" });
            listdata.Add(new DADirective { DirectiveName = "Filter USD currency records", DirectiveDescription = "Filter those rows where currency is USD" });

            lbDirectiveList.ItemsSource = listdata;
        }

private void btnNewDirectiveClicked(object sender, RoutedEventArgs e)
        {
            gDirectiveDetails.IsEnabled = true;
            gDerivedCondition.IsEnabled = true;
            DADirective dirdata = new DADirective { };
            
                   if (!listdata.Contains(dirdata))
            {
                    if (listdata.Count >= 0)
                    {
                        listdata.Add(new DADirective { });
                        lbDirectiveList.SelectedIndex = listdata.Count - 1;
                        txtDirectiveName.Focus();
                    }
                }
            
        }

<ListBox Grid.Row="1" Grid.Column="2" x:Name="lbDirectiveList" ItemsSource="{Binding}" SelectionChanged="lbDirectiveList_SelectionChanged" MaxHeight="200" SelectionMode="Single" ScrollViewer.VerticalScrollBarVisibility="Auto">
                            <ListBox.ItemTemplate>
                                <DataTemplate>
                                    <Grid Margin="4">
                                        <Grid.ColumnDefinitions>
                                            <ColumnDefinition Width="Auto" />
                                            <ColumnDefinition Width="25" />
                                            <ColumnDefinition Width="*" />
                                        </Grid.ColumnDefinitions>

                                        <TextBlock Name="tbDirName" Text="{Binding Path=DirectiveName, Mode=TwoWay}" Grid.Column="0" FontWeight="Bold" MinWidth="200"/>
                                        <TextBlock Text=" - " Grid.Column="1"/>
                                        <TextBlock Grid.Column="2" Name="tbDirDesc" Text="{Binding Path=DirectiveDescription, Mode=TwoWay}" />
                                    </Grid>
                                </DataTemplate>
                            </ListBox.ItemTemplate>
                        </ListBox>

public interface IBookDataService
{
    event EventHandler<HasChangesEventArgs> NotifyHasChanges;
    void Save(Action<SubmitOperation> submitCallback, object state);
    void GetBooksByCategory(
        Action<ObservableCollection<Book>> getBooksCallback,
        int categoryID,
        int pageSize);
    void GetCategories(Action<ObservableCollection<Category>> getCategoriesCallback);
}

public class BookDataService : IBookDataService
   {
       private LoadOperation<Book> _booksLoadOperation;
       private LoadOperation<Category> _categoriesLoadOperation;

       private Action<ObservableCollection<Book>> _getBooksCallback;
       private Action<ObservableCollection<Category>> _getCategoriesCallback;

       private int _pageIndex = 0;
       private BookClubContext Context { get; set; }
       public event EventHandler<HasChangesEventArgs> NotifyHasChanges;

       public BookDataService()
       {
           Context = new BookClubContext();
           Context.PropertyChanged += ContextPropertyChanged;
       }


       private void ContextPropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
       {
           if (NotifyHasChanges != null)
           {
               NotifyHasChanges(this, new HasChangesEventArgs(){HasChanges  = Context.HasChanges});
           }
       }

       public void Save(Action<SubmitOperation> submitCallback, object state)
       {
           if (Context.HasChanges)
           {
               Context.SubmitChanges(submitCallback, state);
           }
       }

       public void GetBooksByCategory(
           Action<ObservableCollection<Book>> getBooksCallback,
           int categoryID,
           int pageSize)
       {
           ClearBooks();
           var query = Context.GetBooksByCategoryQuery(categoryID).Take(pageSize);
           RunBooksQuery(query, getBooksCallback);
       }

       public void GetBooksByTitle(Action<ObservableCollection<Book>> getBooksCallback, int categoryID, string titleFilter)
       {
           ClearBooks();
           var query = Context.GetBooksByCategoryQuery(categoryID)
               .Where(b => b.Title.Contains(titleFilter));
           RunBooksQuery(query, getBooksCallback);
       }

       private void ClearBooks()
       {
           _pageIndex = 0;
           Context.Books.Clear();
       }

       private void RunBooksQuery(EntityQuery<Book> query, Action<ObservableCollection<Book>> getBooksCallback)
       {
           _getBooksCallback = getBooksCallback;
           _booksLoadOperation = Context.Load<Book>(query);
           _booksLoadOperation.Completed += OnLoadBooksCompleted;
       }

       private void OnLoadBooksCompleted(object sender, EventArgs e)
       {
           _booksLoadOperation.Completed -= OnLoadBooksCompleted;
           var books = new EntityList<Book>(Context.Books, _booksLoadOperation.Entities);
           _getBooksCallback(books);
       }

       public void GetCategories(Action<ObservableCollection<Category>> getCategoriesCallback)
       {
           _getCategoriesCallback = getCategoriesCallback;
           Context.Categories.Clear();
           _categoriesLoadOperation = Context.Load<Category>(Context.GetCategoriesQuery());
           _categoriesLoadOperation.Completed += OnLoadCategoriesCompleted;
       }

       private void OnLoadCategoriesCompleted(object sender, EventArgs e)
       {
           _categoriesLoadOperation.Completed -= OnLoadCategoriesCompleted;
           var categories = new EntityList<Category>(Context.Categories, _categoriesLoadOperation.Entities);
           _getCategoriesCallback(categories);
       }
   }

 public void LoadBooksByCategory()
 {
     //Books.Clear();
     Books = null;
     if (SelectedCategory != null)
         BookDataService.GetBooksByCategory(GetBooksCallback, SelectedCategory.CategoryID, _pageSize);
 }

private void GetBooksCallback(ObservableCollection<Book> books)
 {
     if (books != null)
     {
         if (Books == null)
         {
             Books = books;
         }
         else
         {
             foreach (var book in books)
             {
                 Books.Add(book);
             }
         }

         if (Books.Count > 0)
         {
             SelectedBook = Books[0];
         }

     }
 }