How to bind an ancestor from a datatemplate generated descendant

Question

Hello to the forum,
I have a listbox whose data source is a collection of items (collection A).
Every item of the collection includes itself another collection of elements (collection B).
I use a datatemplate to present the listbox as a stack of blocks and to display inside
each block a tree of elements whose data source is the collection B.

If selecting a node of the datatemplate generated sub-tree,
I want the container listbox item to be selected as well.
Is it possible to bind ancestors' properties using as source the template-generated
descendants' properties?

I wasn't able to find a solution for this issue.

This is the xaml of my datatempate:

<DataTemplate x:Key="listBoxTemplate">
   <Grid>
      <Grid.RowDefinitions>
         <RowDefinition/>
         <RowDefinition/>
      </Grid.RowDefinitions>
      <Grid.ColumnDefinitions>
         <ColumnDefinition Width="Auto"/>
      </Grid.ColumnDefinitions>
      <TextBlock Name="tbxRole" Grid.Row="0" Grid.Column="0" Text="{Binding Path=ValueMember.Type.Name}"/>
      <TreeView Name="subTree" Grid.Row="1" Grid.Column="0" ItemsSource="{Binding Path=ChildrenItems}">
         <TreeView.ItemTemplate>
            <HierarchicalDataTemplate DataType="root" ItemsSource="{Binding Path=ChildrenItems}">
               <StackPanel Orientation="Horizontal">
                  <TextBlock Name="linkTypeName" Text="{Binding Path=ValueMember.LinkType.Name}"/>
                  <TextBlock Name="linkName" Text="{Binding Path=ValueMember.IdentityRefChild.LastName}"/>
               </StackPanel>
            </HierarchicalDataTemplate>
         </TreeView.ItemTemplate>
      </TreeView>
   </Grid>
</DataTemplate>

Thanks for help in advance.

Gianni

Answer 1

You can get ListBoxItem from TreeView.GotFocus event. The following code shows how to do this.

 

Code Snippet

<Window

   x:Class="ForumProjects.MainWindow"

   xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

   xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

   xmlns:local="clr-namespace:ForumProjects"

   x:Name="Window">

    <Window.Resources>

        <DataTemplate x:Key="OrderItemTemplate">

            <TextBlock Text="{Binding Product}"/>

        </DataTemplate>

        <HierarchicalDataTemplate x:Key="OrderTemplate"

                                ItemsSource="{Binding Items}"

                                ItemTemplate="{StaticResource OrderItemTemplate}">

            <TextBlock Text="{Binding OrderID}"/>

        </HierarchicalDataTemplate>

        <DataTemplate x:Key="CustomerTemplate">

            <StackPanel>

                <TextBlock Text="{Binding Name}"/>

                <TreeView ItemsSource="{Binding Orders}"

                        ItemTemplate="{StaticResource OrderTemplate}"

                        GotFocus="TreeViewGotFocus"/>

            </StackPanel>

        </DataTemplate>

    </Window.Resources>

    <ListBox ItemsSource="{Binding ElementName=Window, Path=Customers}"

            ItemTemplate="{StaticResource CustomerTemplate}"/>

</Window>

 

namespace ForumProjects

{

    public partial class MainWindow : Window

    {

        public MainWindow()

        {

            this.Customers = new List<Customer>()

            {

                new Customer("Customer A"),

                new Customer("Customer B")

            };

 

            this.Customers[0].Orders.AddRange(new Order[]

            {

                new Order("0001"),

                new Order("0002")

            });

            this.Customers[0].Orders[0].Items.AddRange(new OrderItem[]

            {

                new OrderItem("Product A"),

                new OrderItem("Product B")

            });

            this.Customers[0].Orders[1].Items.AddRange(new OrderItem[]

            {

                new OrderItem("Product C"),

                new OrderItem("Product D")

            });

 

            this.Customers[1].Orders.AddRange(new Order[]

            {

                new Order("0001"),

                new Order("0002")

            });

            this.Customers[1].Orders[0].Items.AddRange(new OrderItem[]

            {

                new OrderItem("Product A"),

                new OrderItem("Product B")

            });

            this.Customers[1].Orders[1].Items.AddRange(new OrderItem[]

            {

                new OrderItem("Product C"),

                new OrderItem("Product D")

            });

            InitializeComponent();

        }

 

        private void TreeViewGotFocus(object sender, RoutedEventArgs e)

        {

            ContentPresenter presenter = (ContentPresenter)(((StackPanel)((TreeView)e.Source).Parent).TemplatedParent);

            Customer customer = (Customer)presenter.Content;

            ((ListBox)this.Content).SelectedItem = customer;

        }

 

        public List<Customer> Customers { get; private set; }

    }

    public class Customer

    {

        public Customer(string name) { this.Orders = new List<Order>(); this.Name = name; }

        public string Name { get; set; }

        public List<Order> Orders { get; private set; }

    }

    public class Order

    {

        public Order(string id) { this.Items = new List<OrderItem>(); this.OrderID = id; }

        public string OrderID { get; set; }

        public List<OrderItem> Items { get; private set; }

    }

    public class OrderItem

    {

        public OrderItem(string product) { this.Product = product; }

        public string Product { get; set; }

    }

}

 

 

Best Regards,

Wei Zhou