Products = new ObservableCollection<Product>(products);
ProductOptions = new ObservableCollection<ProductOption>(options);
ProductsView = CollectionViewSource.GetDefaultView(Products);
ProductsView.GroupDescriptions.Add(new PropertyGroupDescription("Group"));
ProductsView.SortDescriptions.Add(
new SortDescription("Name", ListSortDirection.Ascending));
ProductOptionsView = CollectionViewSource.GetDefaultView(ProductOptions);
ProductOptionsView.SortDescriptions.Add(
new SortDescription("Option", ListSortDirection.Ascending));
<ListBox Grid.Row="1" ItemsSource="{Binding Products}"
DisplayMemberPath="Name">
<ListBox.GroupStyle>
<GroupStyle>
<GroupStyle.HeaderTemplate>
<DataTemplate>
<TextBlock Foreground="DarkGreen" Text="{Binding Name}"
FontStyle="Italic"/>
</DataTemplate>
</GroupStyle.HeaderTemplate>
</GroupStyle>
</ListBox.GroupStyle>