Data binding to SelectedItem in a WPF Treeview

by

I realise this has already had an answer accepted, but I put this together to solve the problem. It uses a similar idea to Delta’s solution, but without the need to subclass the TreeView:

public class BindableSelectedItemBehavior : Behavior<TreeView>
{
    #region SelectedItem Property

    public object SelectedItem
    {
        get { return (object)GetValue(SelectedItemProperty); }
        set { SetValue(SelectedItemProperty, value); }
    }

    public static readonly DependencyProperty SelectedItemProperty =
        DependencyProperty.Register("SelectedItem", typeof(object), typeof(BindableSelectedItemBehavior), new UIPropertyMetadata(null, OnSelectedItemChanged));

    private static void OnSelectedItemChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
    {
        var item = e.NewValue as TreeViewItem;
        if (item != null)
        {
            item.SetValue(TreeViewItem.IsSelectedProperty, true);
        }
    }

    #endregion

    protected override void OnAttached()
    {
        base.OnAttached();

        this.AssociatedObject.SelectedItemChanged += OnTreeViewSelectedItemChanged;
    }

    protected override void OnDetaching()
    {
        base.OnDetaching();

        if (this.AssociatedObject != null)
        {
            this.AssociatedObject.SelectedItemChanged -= OnTreeViewSelectedItemChanged;
        }
    }

    private void OnTreeViewSelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e)
    {
        this.SelectedItem = e.NewValue;
    }
}

You can then use this in your XAML as:

<TreeView>
    <e:Interaction.Behaviors>
        <behaviours:BindableSelectedItemBehavior SelectedItem="{Binding SelectedItem, Mode=TwoWay}" />
    </e:Interaction.Behaviors>
</TreeView>

Hopefully it will help someone!

More Related Contents:

  1. WPF MVVM navigate views
  2. Set focus on TextBox in WPF from view model
  3. Why RelayCommand
  4. How do I bind a TabControl to a collection of ViewModels?
  5. How to handle dependency injection in a WPF/MVVM application
  6. This type of CollectionView does not support changes to its SourceCollection from a thread different from the Dispatcher thread [duplicate]
  7. Bind to SelectedItems from DataGrid or ListBox in MVVM
  8. How to implement a progress bar using the MVVM pattern
  9. WPF TreeView HierarchicalDataTemplate – binding to object with multiple child collections
  10. MVVM in WPF – How to alert ViewModel of changes in Model… or should I?
  11. MVVM Light & WPF – Binding Multiple instances of a Window to a ViewModel
  12. Binding an Image in WPF MVVM
  13. Give some command to View in MVVM
  14. How to support ListBox SelectedItems binding with MVVM in a navigable application
  15. WPF/MVVM – how to handle double-click on TreeViewItems in the ViewModel?
  16. WPF binding not updating the view
  17. Should I bind to ICollectionView or ObservableCollection
  18. Two-way binding of Xml data to the WPF TreeView
  19. WPF: How to bind a command to the ListBoxItem using MVVM?
  20. ObservableCollection not updating View
  21. The component does not have a resource identified by the uri
  22. Having HierarchicalDataTemplates in a TreeView
  23. ScrollIntoView for WPF DataGrid (MVVM)
  24. Select item programmatically in WPF ListView
  25. Binding Commands to Events?
  26. How to have multiple pairs “View-ViewModel”?
  27. WPF ListView SelectedItem is null
  28. Accessing a property in one ViewModel from another
  29. Add context menu in datagrid, how to get the select Item value
  30. Is it wrong to use the Dispatcher within my ViewModel?

Leave a Comment