Develop Reference

WPF Listbox focus from viewmodel

I've stumbled upon the well-known problem with Listbox and focus. I'm setting ItemsSource from the viewmodel and at some point I need to reload them and set selection and focus to a specific item, say:
private readonly ObservableCollection<ItemViewModel> items;
private ItemViewModel selectedItem;
private void Process()
{
items.Clear();
for (int i = 0; i < 100; i++)
{
items.Add(new ItemViewModel(i));
}
var item = items.FirstOrDefault(i => i.Value == 25);
SelectedItem = item;
}
public ObservableCollection<ItemViewModel> Items { /* usual stuff */ }
public ItemViewModel SelectedItem { /* usual stuff */ }
Binding may look like:
<ListBox ItemsSource="{Binding Items}" SelectedItem="{Binding SelectedItem}" />
After calling the method item gets selected, but does not receive focus.
I've read a lot on the Internet and on StackOverflow, but all answers I found involve manual filling of the listbox, not via binding from viewmodel. So the question is: how can I properly focus newly selected item in the presented scenario?
To add some context, I'm implementing a sidebar file browser:
I need keyboard navigation on the listbox below treeview.

Here is a solution that might work for you:
The control:
class FocusableListBox : ListBox
{
#region Dependency Proeprty
public static readonly DependencyProperty IsFocusedControlProperty = DependencyProperty.Register("IsFocusedControl", typeof(Boolean), typeof(FocusableListBox), new UIPropertyMetadata(false, OnIsFocusedChanged));
public Boolean IsFocusedControl
{
get { return (Boolean)GetValue(IsFocusedControlProperty); }
set { SetValue(IsFocusedControlProperty, value); }
}
public static void OnIsFocusedChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs dependencyPropertyChangedEventArgs)
{
ListBox listBox = dependencyObject as ListBox;
listBox.Focus();
}
#endregion Dependency Proeprty
}
The ViewModel:
class ViewModel : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private Boolean _IsFocused;
private String selectedItem;
public ObservableCollection<String> Items { get; private set; }
public String SelectedItem
{
get
{
return selectedItem;
}
set
{
selectedItem = value;
RaisePropertyChanged("SelectedItem");
}
}
public Boolean IsFocused
{
get { return _IsFocused; }
set
{
_IsFocused = value;
RaisePropertyChanged("IsFocused");
}
}
public ViewModel()
{
Items = new ObservableCollection<string>();
Process();
}
private void Process()
{
Items.Clear();
for (int i = 0; i < 100; i++)
{
Items.Add(i.ToString());
}
ChangeFocusedElement("2");
}
public void ChangeFocusedElement(string newElement)
{
var item = Items.FirstOrDefault(i => i == newElement);
IsFocused = false;
SelectedItem = item;
IsFocused = true;
}
private void RaisePropertyChanged(String propName)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propName));
}
}
The XAML:
<local:FocusableListBox ItemsSource="{Binding Items}" SelectedItem="{Binding SelectedItem}"
HorizontalAlignment="Left" VerticalAlignment="Stretch"
ScrollViewer.VerticalScrollBarVisibility="Auto"
Width="200"
IsFocusedControl="{Binding IsFocused, Mode=TwoWay}"/>
The update call:
_viewModel.ChangeFocusedElement("10");

I ended up with the following code in control's codebehind:
public void FixListboxFocus()
{
if (lbFiles.SelectedItem != null)
{
lbFiles.ScrollIntoView(lbFiles.SelectedItem);
lbFiles.UpdateLayout();
var item = lbFiles.ItemContainerGenerator.ContainerFromItem(viewModel.SelectedFile);
if (item != null && item is ListBoxItem listBoxItem && !listBoxItem.IsFocused)
listBoxItem.Focus();
}
}
This method is available for calling from within viewModel, which calls it every time it sets the selection:
var file = files.FirstOrDefault(f => f.Path.Equals(subfolderName, StringComparison.OrdinalIgnoreCase));
if (file != null)
SelectedFile = file;
else
SelectedFile = files.FirstOrDefault();
access.FixListboxFocus();
The access is view passed to ViewModel via interface (to keep separation between presentation and logic). The relevant XAML part looks like following:
<ListBox x:Name="lbFiles" ItemsSource="{Binding Files}" SelectedItem="{Binding SelectedFile}" />

Bindable property not working in user control wpf

I have User Control and create DepedencyProperty "ItemSource" inside that user control like this
public static readonly DependencyProperty ItemsSourceProperty =
DependencyProperty.Register(
"ItemsSource", typeof(IEnumerable), typeof(DataGridFilterDetail),
new PropertyMetadata(new PropertyChangedCallback(OnItemsSourcePropertyChanged)));
public IEnumerable ItemsSource
{
get
{
return (IEnumerable)GetValue(ItemsSourceProperty);
}
set
{
SetValue(ItemsSourceProperty, value);
NotifyPropertyChanged("ItemsSource");
}
}
static void OnItemsSourcePropertyChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
{
var control = sender as DataGridFilterDetail;
if (control != null)
{
control.OnItemsSourceChanged((IEnumerable)e.OldValue(IEnumerable)e.NewValue);
}
}
void OnItemsSourceChanged(IEnumerable oldValue, IEnumerable newValue)
{
// Remove handler for oldValue.CollectionChanged
var oldValueINotifyCollectionChanged = oldValue as INotifyCollectionChanged;
if (null != oldValueINotifyCollectionChanged)
{
oldValueINotifyCollectionChanged.CollectionChanged -= new NotifyCollectionChangedEventHandler(newValueINotifyCollectionChanged_CollectionChanged);
}
// Add handler for newValue.CollectionChanged (if possible)
var newValueINotifyCollectionChanged = newValue as INotifyCollectionChanged;
if (null != newValueINotifyCollectionChanged)
{
newValueINotifyCollectionChanged.CollectionChanged += new NotifyCollectionChangedEventHandler(newValueINotifyCollectionChanged_CollectionChanged);
}
}
void newValueINotifyCollectionChanged_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
if (e.NewItems == null)
{
TotalCount = 0;
}
else
{
TotalCount = e.NewItems.Count;
}
}
And then i bind "ItemSource" into ItemSource of my DataGrid inside UserControl like this.
<UserControl x:Class="WPF.Controls.DataGridFilterDetail" x:Name="dataGridFilterDetail" .../>
<DataGrid ItemsSource="{Binding ElementName=dataGridFilterDetail,Path=ItemsSource}" AutoGenerateColumns="True"/>
</UserControl>
and then i using this user control inside my view.
<UserControl x:Class="Project.View.MyView" ..
<UserControl.Resources>
<vm:MyViewModel x:Key="myViewModel" />
</UserControl.Resources>
<Grid>
<custom:DataGridFilterDetail ItemsSource="{Binding GridItemCollections, Source={StaticResource myViewModel}}" />
</Grid>
</UserControl>
inside MyView.cs Constructor i set my view datacontext :
public MyView()
{
InitializeComponent();
myViewModel= (MyViewModel)this.Resources["myViewModel"];
this.DataContext = myViewModel;
}
on myViewModel i create property "GridItemCollections" like this
private ObservableCollection<myCustomClass> gridItemCollections;
public ObservableCollection<myCustomClass> GridItemCollections
{
get { return gridItemCollections; }
set
{
gridItemCollections = value;
NotifyPropertyChanged("GridItemCollections");
}
}
public void AddNewGridRow()
{
GridItemCollections.Add(CurrentDetail);
}
now the problem is, why grid inside user control not updating when i modify "GridItemCollections" on my view model?is there something that i missing here?
Thanks in advance.

How to select an item in LongListSelector using the MVVM-pattern?

I'm building application using the MVVM pattern. After clicking on one of the elements I want to see this element's details. I wrote this:
XAML
<phone:LongListSelector ItemsSource="{Binding Data}"
Margin="0,0,0,158"
SelectedItem="{Binding SelectedItem}">
<phone:LongListSelector.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<Button>
<!-- Command="{Binding ShowDetailsAction}"-->
<Button.Template>
<ControlTemplate>
<TextBlock Text="{Binding Text}"></TextBlock>
</ControlTemplate>
</Button.Template>
</Button>
</StackPanel>
</DataTemplate>
</phone:LongListSelector.ItemTemplate>
</phone:LongListSelector>
ViewModel:
public IEnumerable SelectedItem
{
get { return _itemsControl; }
set
{
if (_itemsControl == value)
return;
_itemsControl = value;
// Test
_mss.ErrorNotification("fd");
}
}
I tried also using a command, which didn't work, too.
This was the command part:
public ICommand ShowDetailsCommand { get; private set; }
public ViewModel()
{
_loadDataCommand = new DelegateCommand(LoadDataAction);
SaveChangesCommand = new DelegateCommand(SaveChangesAction);
ShowDetailsCommand = new DelegateCommand(ShowDetailsAction);
}
private void ShowDetailsAction(object p)
{
_mss.ErrorNotification("bla bla");
}
EDIT
ViewModel
private IEnumerable _itemsControl;
public IEnumerable Data
{
get
{
return _itemsControl;
}
set
{
_itemsControl = value;
RaisePropertyChanged("Data");
}
}
protected void RaisePropertyChanged(string propertyName)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(propertyName));
}
}
Model
public string Text { get; set; }
public DateTimeOffset Data { get; set; }
EDIT2
private MobileServiceCollection<ModelAzure, ModelAzure> _items;
private readonly IMobileServiceTable<ModelAzure> _todoTable = App.MobileService.GetTable<ModelAzure>();
private async void RefreshTodoItems()
{
try
{
_items = await _todoTable.ToCollectionAsync();
}
catch (MobileServiceInvalidOperationException e)
{
_mss.ErrorNotification(e.ToString());
}
Data = _items;
}

Your Data property looks like
private MobileServiceCollection<ModelAzure, ModelAzure> _itemsControl;
public MobileServiceCollection<ModelAzure, ModelAzure> Data
{
get
{
return _itemsControl;
}
set
{
_itemsControl = value;
RaisePropertyChanged("Data");
}
}
Edited
It seems the SelectedItem property from LongListSelector cannot be bound in WP8.
What you can do is either :
Use the derived and fixed custom LongListSelector provided in the link above instead of the default one, which looks like :
public class LongListSelector : Microsoft.Phone.Controls.LongListSelector
{
public LongListSelector()
{
SelectionChanged += LongListSelector_SelectionChanged;
}
void LongListSelector_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
SelectedItem = base.SelectedItem;
}
public static readonly DependencyProperty SelectedItemProperty =
DependencyProperty.Register(
"SelectedItem",
typeof(object),
typeof(LongListSelector),
new PropertyMetadata(null, OnSelectedItemChanged)
);
private static void OnSelectedItemChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var selector = (LongListSelector)d;
selector.SelectedItem = e.NewValue;
}
public new object SelectedItem
{
get { return GetValue(SelectedItemProperty); }
set { SetValue(SelectedItemProperty, value); }
}
}
Register the SelectionChanged event from LongListSelector and call your ViewModel by yourself inside the associated handler/callback :
in your view :
<phone:LongListSelector x:Name="YourLongListSelectorName"
ItemsSource="{Binding Data}"
Margin="0,0,0,158"
SelectionChanged="OnSelectedItemChanged">
in your code behind :
private void OnSelectedItemChanged(object sender, SelectionChangedEventArgs selectionChangedEventArgs e)
{
((YourViewModel)this.DataContext).NewSelectedItemMethodOrWhateverYouWant((ModelAzure)this.YourLongListSelectorName.SelectedItem);
//or
((YourViewModel)this.DataContext).SelectedItem = (ModelAzure)this.YourLongListSelectorName.SelectedItem;
}
Finally your Button command wasn't properly working, because when you use a DataTemplate, the ambiant DataContext is the item itself. Which means that it was looking for your Command into your Model instance, not into your ViewModel instance.
Hope this helps

In your ViewModel, you have:
public IEnumerable SelectedItem
{
get { return _itemsControl; }
set
{
if (_itemsControl == value)
return;
_itemsControl = value;
// Test
_mss.ErrorNotification("fd");
}
}
Why is your SelectItem an IEnumerable? Should it not be of type "Model"? Your list is bound to "Data" which should be ObservableList, not IEnumerable. It will provide it's own change notification, so you don't need to.
The list will set the SelectedItem when it gets selected, but if the type is wrong, it won't get set.
Greg

WPF ComboBox Binding works if previous record had no matching item in the ItemsSource collection and fails if it did

I have the following WPF Combobox:
<Window.Resources>
<CollectionViewSource x:Key="performanceItemsource" Source="{Binding Path=SelectedReport.Performances}" >
<CollectionViewSource.SortDescriptions>
<scm:SortDescription PropertyName="Name"/>
</CollectionViewSource.SortDescriptions>
</CollectionViewSource>
</Window.Resources>
...
<ComboBox Name="cbxPlanPerf" Grid.ColumnSpan="2"
SelectedValuePath="MSDPortfolioID" DisplayMemberPath="Name"
SelectedValue="{Binding Path=PlanPerfID}"
ItemsSource="{Binding Source={StaticResource performanceItemsource}}"/>
The Source for the CollectionViewSource is:
public List<MSDExportProxy> Performances
{
get
{
if (Portfolio != null)
{
return (from a in Portfolio.Accounts where a.MSDPortfolioID != null select new MSDExportProxy(a))
.Concat<MSDExportProxy>(from g in Portfolio.Groups where g.MSDPortfolioID != null select new MSDExportProxy(g))
.Concat<MSDExportProxy>(from p in new[] { Portfolio } where p.MSDPortfolioID != null select new MSDExportProxy(p))
.ToList<MSDExportProxy>();
}
return new List<MSDExportProxy>();
}
}
The bound property PlanPerfID is a string.
I move between records using a ListBox control. The ComboBox works fine if the previous record had no items in its ComboBox.ItemsSource. If there were any items in the previous record's ComboBox.ItemsSource then the new record won't find its matching item in the ItemsSource collection. I've tried setting the ItemsSource in both XAML and the code-behind, but nothing changes this odd behavior. How can I get this darn thing to work?

Try using ICollectionViews in combination with IsSynchronizedWithCurrentItem property when handling lists / ObservableCollection in Xaml. The ICollectionView in the viewmodel can handle all the things needed, e.g. sorting, filtering, keeping track of selections and states.
Xaml:
<Window x:Class="ComboBoxBinding.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition />
<ColumnDefinition />
</Grid.ColumnDefinitions>
<ListBox Grid.Column="0"
ItemsSource="{Binding Reports}"
DisplayMemberPath="Name"
IsSynchronizedWithCurrentItem="True" />
<ComboBox Grid.Column="1"
ItemsSource="{Binding CurrentReport.Performances}"
DisplayMemberPath="Name"
IsSynchronizedWithCurrentItem="True" />
</Grid>
</Window>
ViewModel:
public class ViewModel : INotifyPropertyChanged
{
private readonly IReportService _reportService;
private ObservableCollection<ReportViewModel> _reports = new ObservableCollection<ReportViewModel>();
private PerformanceViewModel _currentPerformance;
private ReportViewModel _currentReport;
public ObservableCollection<ReportViewModel> Reports
{
get { return _reports; }
set { _reports = value; OnPropertyChanged("Reports");}
}
public ReportViewModel CurrentReport
{
get { return _currentReport; }
set { _currentReport = value; OnPropertyChanged("CurrentReport");}
}
public PerformanceViewModel CurrentPerformance
{
get { return _currentPerformance; }
set { _currentPerformance = value; OnPropertyChanged("CurrentPerformance");}
}
public ICollectionView ReportsView { get; private set; }
public ICollectionView PerformancesView { get; private set; }
public ViewModel(IReportService reportService)
{
if (reportService == null) throw new ArgumentNullException("reportService");
_reportService = reportService;
var reports = _reportService.GetData();
Reports = new ObservableCollection<ReportViewModel>(reports);
ReportsView = CollectionViewSource.GetDefaultView(Reports);
ReportsView.SortDescriptions.Add(new SortDescription("Name", ListSortDirection.Ascending));
ReportsView.CurrentChanged += OnReportsChanged;
ReportsView.MoveCurrentToFirst();
}
private void OnReportsChanged(object sender, EventArgs e)
{
var selectedReport = ReportsView.CurrentItem as ReportViewModel;
if (selectedReport == null) return;
CurrentReport = selectedReport;
if(PerformancesView != null)
{
PerformancesView.CurrentChanged -= OnPerformancesChanged;
}
PerformancesView = CollectionViewSource.GetDefaultView(CurrentReport.Performances);
PerformancesView.SortDescriptions.Add(new SortDescription("Name", ListSortDirection.Ascending));
PerformancesView.CurrentChanged += OnPerformancesChanged;
PerformancesView.MoveCurrentToFirst();
}
private void OnPerformancesChanged(object sender, EventArgs e)
{
var selectedperformance = PerformancesView.CurrentItem as PerformanceViewModel;
if (selectedperformance == null) return;
CurrentPerformance = selectedperformance;
}
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged(string propertyName)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
}
}

I found a quick and dirty solution to my problem. I just happen to have a public NotifyPropertyChanged() method on my Report entity and I discovered that if I called SelectedReport.NotifyPropertyChanged("PlanPerfID") in the Report ListBox's SelectionChanged event that it was enough of a jolt to get the ComboBox to re-evaluate and find its matching item in the ItemsSource. Yeah, it's KLUGE...
UPDATE: I also wound up needing to add SelectedReport.NotifyPropertyChanged("Performances") for some situations...
UPDATE 2: Okay, turns out the above wasn't bullet proof and I ran across a situation that broke it so I had to come up with a better workaround:
Altered the SelectedReport property in the Window's code-behind, adding a private flag (_settingCombos) to keep the Binding from screwing up the bound values until the dust has settled from changin the ItemSource:
private bool _settingCombos = false;
private Report _SelectedReport;
public Report SelectedReport
{
get { return _SelectedReport; }
set
{
_settingCombos = true;
_SelectedReport = value;
NotifyPropertyChanged("SelectedReport");
}
}
Created a proxy to bind to in the Window code-behind that will refuse to update the property's value if the _settingCombos flag is true:
public string PlanPerfID_Proxy
{
get { return SelectedReport.PlanPerfID; }
set
{
if (!_settingCombos)
{
SelectedReport.PlanPerfID = value;
NotifyPropertyChanged("PlanPerfID_Proxy");
}
}
}
Added an extra Notification in the Report ListBox's SelectionChanged event along with code to reset the _settingCombos flag back to false:
private void lbxReports_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
//KLUGE: Couldn't get the ComboBoxes associated with these properties to work right
//this forces them to re-evaluate after the Report has loaded
if (SelectedReport != null)
{
NotifyPropertyChanged("PlanPerfID_Proxy");
_settingCombos = false;
}
}
Bound the ComboBox to the PlanPerfID_Proxy property (instead of directly to the SelectedReport.PlanPerfID property.
Wow, what a hassle! I think that this is simply a case of .NET's binding logic getting confused by the dynamic nature of the ComboBox.ItemSource, but this seems to have fixed it. Hope it helps someone else.

Data binding to SelectedItem in a WPF Treeview

How can I retrieve the item that is selected in a WPF-treeview? I want to do this in XAML, because I want to bind it.
You might think that it is SelectedItem but apparently that does not exist is readonly and therefore unusable.
This is what I want to do:
<TreeView ItemsSource="{Binding Path=Model.Clusters}"
ItemTemplate="{StaticResource ClusterTemplate}"
SelectedItem="{Binding Path=Model.SelectedCluster}" />
I want to bind the SelectedItem to a property on my Model.
But this gives me the error:
'SelectedItem' property is read-only and cannot be set from markup.
Edit:
Ok, this is the way that I solved this:
<TreeView
ItemsSource="{Binding Path=Model.Clusters}"
ItemTemplate="{StaticResource HoofdCLusterTemplate}"
SelectedItemChanged="TreeView_OnSelectedItemChanged" />
and in the codebehindfile of my xaml:
private void TreeView_OnSelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e)
{
Model.SelectedCluster = (Cluster)e.NewValue;
}

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!

This property exists : TreeView.SelectedItem
But it is readonly, so you cannot assign it through a binding, only retrieve it

Well, I found a solution. It moves the mess, so that MVVM works.
First add this class:
public class ExtendedTreeView : TreeView
{
public ExtendedTreeView()
: base()
{
this.SelectedItemChanged += new RoutedPropertyChangedEventHandler<object>(___ICH);
}
void ___ICH(object sender, RoutedPropertyChangedEventArgs<object> e)
{
if (SelectedItem != null)
{
SetValue(SelectedItem_Property, SelectedItem);
}
}
public object SelectedItem_
{
get { return (object)GetValue(SelectedItem_Property); }
set { SetValue(SelectedItem_Property, value); }
}
public static readonly DependencyProperty SelectedItem_Property = DependencyProperty.Register("SelectedItem_", typeof(object), typeof(ExtendedTreeView), new UIPropertyMetadata(null));
}
and add this to your xaml:
<local:ExtendedTreeView ItemsSource="{Binding Items}" SelectedItem_="{Binding Item, Mode=TwoWay}">
.....
</local:ExtendedTreeView>

It answers a little more than the OP is expecting... But I hope it could help some one at least.
If you want to execute a ICommand whenever the SelectedItem changed, you can bind a command on an event and the use of a property SelectedItem in the ViewModel isn't needed anymore.
To do so:
1- Add reference to System.Windows.Interactivity
xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
2- Bind the command to the event SelectedItemChanged
<TreeView x:Name="myTreeView" Margin="1"
ItemsSource="{Binding Directories}">
<i:Interaction.Triggers>
<i:EventTrigger EventName="SelectedItemChanged">
<i:InvokeCommandAction Command="{Binding SomeCommand}"
CommandParameter="
{Binding ElementName=myTreeView
,Path=SelectedItem}"/>
</i:EventTrigger>
</i:Interaction.Triggers>
<TreeView.ItemTemplate>
<!-- ... -->
</TreeView.ItemTemplate>
</TreeView>

This can be accomplished in a 'nicer' way using only binding and the GalaSoft MVVM Light library's EventToCommand. In your VM add a command which will be called when the selected item is changed, and initialize the command to perform whatever action is necessary. In this example I used a RelayCommand and will just set the SelectedCluster property.
public class ViewModel
{
public ViewModel()
{
SelectedClusterChanged = new RelayCommand<Cluster>( c => SelectedCluster = c );
}
public RelayCommand<Cluster> SelectedClusterChanged { get; private set; }
public Cluster SelectedCluster { get; private set; }
}
Then add the EventToCommand behavior in your xaml. This is really easy using blend.
<TreeView
x:Name="lstClusters"
ItemsSource="{Binding Path=Model.Clusters}"
ItemTemplate="{StaticResource HoofdCLusterTemplate}">
<i:Interaction.Triggers>
<i:EventTrigger EventName="SelectedItemChanged">
<GalaSoft_MvvmLight_Command:EventToCommand Command="{Binding SelectedClusterChanged}" CommandParameter="{Binding ElementName=lstClusters,Path=SelectedValue}"/>
</i:EventTrigger>
</i:Interaction.Triggers>
</TreeView>

All to complicated... Go with Caliburn Micro (http://caliburnmicro.codeplex.com/)
View:
<TreeView Micro:Message.Attach="[Event SelectedItemChanged] = [Action SetSelectedItem($this.SelectedItem)]" />
ViewModel:
public void SetSelectedItem(YourNodeViewModel item) {};

I came across this page looking for the same answer as the original author, and proving there's always more than one way to do it, the solution for me was even easier than the answers provided here so far, so I figured I might as well add to the pile.
The motivation for the binding is to keep it nice & MVVM. The probable usage of the ViewModel is to have a property w/ a name such as "CurrentThingy", and somewhere else, the DataContext on some other thing is bound to "CurrentThingy".
Rather than going through additional steps required (eg: custom behavior, 3rd party control) to support a nice binding from the TreeView to my Model, and then from something else to my Model, my solution was to use simple Element binding the other thing to TreeView.SelectedItem, rather than binding the other thing to my ViewModel, thereby skipping the extra work required.
XAML:
<TreeView x:Name="myTreeView" ItemsSource="{Binding MyThingyCollection}">
.... stuff
</TreeView>
<!-- then.. somewhere else where I want to see the currently selected TreeView item: -->
<local:MyThingyDetailsView
DataContext="{Binding ElementName=myTreeView, Path=SelectedItem}" />
Of course, this is great for reading the currently selected item, but not setting it, which is all I needed.

You might also be able to use TreeViewItem.IsSelected property

My requirement was for PRISM-MVVM based solution where a TreeView was needed and the bound object is of type Collection<> and hence needs HierarchicalDataTemplate. The default BindableSelectedItemBehavior wont be able to identify the child TreeViewItem. To make it to work in this scenario.
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 behavior = sender as BindableSelectedItemBehavior;
if (behavior == null) return;
var tree = behavior.AssociatedObject;
if (tree == null) return;
if (e.NewValue == null)
foreach (var item in tree.Items.OfType<TreeViewItem>())
item.SetValue(TreeViewItem.IsSelectedProperty, false);
var treeViewItem = e.NewValue as TreeViewItem;
if (treeViewItem != null)
treeViewItem.SetValue(TreeViewItem.IsSelectedProperty, true);
else
{
var itemsHostProperty = tree.GetType().GetProperty("ItemsHost", System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance);
if (itemsHostProperty == null) return;
var itemsHost = itemsHostProperty.GetValue(tree, null) as Panel;
if (itemsHost == null) return;
foreach (var item in itemsHost.Children.OfType<TreeViewItem>())
{
if (WalkTreeViewItem(item, e.NewValue))
break;
}
}
}
public static bool WalkTreeViewItem(TreeViewItem treeViewItem, object selectedValue)
{
if (treeViewItem.DataContext == selectedValue)
{
treeViewItem.SetValue(TreeViewItem.IsSelectedProperty, true);
treeViewItem.Focus();
return true;
}
var itemsHostProperty = treeViewItem.GetType().GetProperty("ItemsHost", System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance);
if (itemsHostProperty == null) return false;
var itemsHost = itemsHostProperty.GetValue(treeViewItem, null) as Panel;
if (itemsHost == null) return false;
foreach (var item in itemsHost.Children.OfType<TreeViewItem>())
{
if (WalkTreeViewItem(item, selectedValue))
break;
}
return false;
}
#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;
}
}
This enables to iterate through all the elements irrespective of the level.

I suggest an addition to the behavior provided by Steve Greatrex. His behavior doesn't reflects changes from the source because it may not be a collection of TreeViewItems.
So it is a matter of finding the TreeViewItem in the tree which datacontext is the selectedValue from the source.
The TreeView has a protected property called "ItemsHost", which holds the TreeViewItem collection. We can get it through reflection and walk the tree searching for the selected item.
private static void OnSelectedItemChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
{
var behavior = sender as BindableSelectedItemBehaviour;
if (behavior == null) return;
var tree = behavior.AssociatedObject;
if (tree == null) return;
if (e.NewValue == null)
foreach (var item in tree.Items.OfType<TreeViewItem>())
item.SetValue(TreeViewItem.IsSelectedProperty, false);
var treeViewItem = e.NewValue as TreeViewItem;
if (treeViewItem != null)
{
treeViewItem.SetValue(TreeViewItem.IsSelectedProperty, true);
}
else
{
var itemsHostProperty = tree.GetType().GetProperty("ItemsHost", System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance);
if (itemsHostProperty == null) return;
var itemsHost = itemsHostProperty.GetValue(tree, null) as Panel;
if (itemsHost == null) return;
foreach (var item in itemsHost.Children.OfType<TreeViewItem>())
if (WalkTreeViewItem(item, e.NewValue)) break;
}
}
public static bool WalkTreeViewItem(TreeViewItem treeViewItem, object selectedValue) {
if (treeViewItem.DataContext == selectedValue)
{
treeViewItem.SetValue(TreeViewItem.IsSelectedProperty, true);
treeViewItem.Focus();
return true;
}
foreach (var item in treeViewItem.Items.OfType<TreeViewItem>())
if (WalkTreeViewItem(item, selectedValue)) return true;
return false;
}
This way the behavior works for two-way bindings. Alternatively, it is possible to move the ItemsHost acquisition to the Behavior's OnAttached method, saving the overhead of using reflection every time the binding updates.

There is also a way to create XAML bindable SelectedItem property without using Interaction.Behaviors.
public static class BindableSelectedItemHelper
{
#region Properties
public static readonly DependencyProperty SelectedItemProperty = DependencyProperty.RegisterAttached("SelectedItem", typeof(object), typeof(BindableSelectedItemHelper),
new FrameworkPropertyMetadata(null, OnSelectedItemPropertyChanged));
public static readonly DependencyProperty AttachProperty = DependencyProperty.RegisterAttached("Attach", typeof(bool), typeof(BindableSelectedItemHelper), new PropertyMetadata(false, Attach));
private static readonly DependencyProperty IsUpdatingProperty = DependencyProperty.RegisterAttached("IsUpdating", typeof(bool), typeof(BindableSelectedItemHelper));
#endregion
#region Implementation
public static void SetAttach(DependencyObject dp, bool value)
{
dp.SetValue(AttachProperty, value);
}
public static bool GetAttach(DependencyObject dp)
{
return (bool)dp.GetValue(AttachProperty);
}
public static string GetSelectedItem(DependencyObject dp)
{
return (string)dp.GetValue(SelectedItemProperty);
}
public static void SetSelectedItem(DependencyObject dp, object value)
{
dp.SetValue(SelectedItemProperty, value);
}
private static bool GetIsUpdating(DependencyObject dp)
{
return (bool)dp.GetValue(IsUpdatingProperty);
}
private static void SetIsUpdating(DependencyObject dp, bool value)
{
dp.SetValue(IsUpdatingProperty, value);
}
private static void Attach(DependencyObject sender, DependencyPropertyChangedEventArgs e)
{
TreeListView treeListView = sender as TreeListView;
if (treeListView != null)
{
if ((bool)e.OldValue)
treeListView.SelectedItemChanged -= SelectedItemChanged;
if ((bool)e.NewValue)
treeListView.SelectedItemChanged += SelectedItemChanged;
}
}
private static void OnSelectedItemPropertyChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
{
TreeListView treeListView = sender as TreeListView;
if (treeListView != null)
{
treeListView.SelectedItemChanged -= SelectedItemChanged;
if (!(bool)GetIsUpdating(treeListView))
{
foreach (TreeViewItem item in treeListView.Items)
{
if (item == e.NewValue)
{
item.IsSelected = true;
break;
}
else
item.IsSelected = false;
}
}
treeListView.SelectedItemChanged += SelectedItemChanged;
}
}
private static void SelectedItemChanged(object sender, RoutedEventArgs e)
{
TreeListView treeListView = sender as TreeListView;
if (treeListView != null)
{
SetIsUpdating(treeListView, true);
SetSelectedItem(treeListView, treeListView.SelectedItem);
SetIsUpdating(treeListView, false);
}
}
#endregion
}
You can then use this in your XAML as:
<TreeView helper:BindableSelectedItemHelper.Attach="True"
helper:BindableSelectedItemHelper.SelectedItem="{Binding SelectedItem, Mode=TwoWay}">

I tried all solutions of this questions. No one solved my problem fully. So I think it's better to use such inherited class with redefined property SelectedItem. It will work perfectly if you choose tree element from GUI and if you set this property value in your code
public class TreeViewEx : TreeView
{
public TreeViewEx()
{
this.SelectedItemChanged += new RoutedPropertyChangedEventHandler<object>(TreeViewEx_SelectedItemChanged);
}
void TreeViewEx_SelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e)
{
this.SelectedItem = e.NewValue;
}
#region SelectedItem
/// <summary>
/// Gets or Sets the SelectedItem possible Value of the TreeViewItem object.
/// </summary>
public new object SelectedItem
{
get { return this.GetValue(TreeViewEx.SelectedItemProperty); }
set { this.SetValue(TreeViewEx.SelectedItemProperty, value); }
}
// Using a DependencyProperty as the backing store for MyProperty. This enables animation, styling, binding, etc...
public new static readonly DependencyProperty SelectedItemProperty =
DependencyProperty.Register("SelectedItem", typeof(object), typeof(TreeViewEx),
new FrameworkPropertyMetadata(null, FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, SelectedItemProperty_Changed));
static void SelectedItemProperty_Changed(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e)
{
TreeViewEx targetObject = dependencyObject as TreeViewEx;
if (targetObject != null)
{
TreeViewItem tvi = targetObject.FindItemNode(targetObject.SelectedItem) as TreeViewItem;
if (tvi != null)
tvi.IsSelected = true;
}
}
#endregion SelectedItem
public TreeViewItem FindItemNode(object item)
{
TreeViewItem node = null;
foreach (object data in this.Items)
{
node = this.ItemContainerGenerator.ContainerFromItem(data) as TreeViewItem;
if (node != null)
{
if (data == item)
break;
node = FindItemNodeInChildren(node, item);
if (node != null)
break;
}
}
return node;
}
protected TreeViewItem FindItemNodeInChildren(TreeViewItem parent, object item)
{
TreeViewItem node = null;
bool isExpanded = parent.IsExpanded;
if (!isExpanded) //Can't find child container unless the parent node is Expanded once
{
parent.IsExpanded = true;
parent.UpdateLayout();
}
foreach (object data in parent.Items)
{
node = parent.ItemContainerGenerator.ContainerFromItem(data) as TreeViewItem;
if (data == item && node != null)
break;
node = FindItemNodeInChildren(node, item);
if (node != null)
break;
}
if (node == null && parent.IsExpanded != isExpanded)
parent.IsExpanded = isExpanded;
if (node != null)
parent.IsExpanded = true;
return node;
}
}

WPF MVVM TreeView SelectedItem
... is a better answer, but does not mention a way to get/set the SelectedItem in the ViewModel.
Add a IsSelected boolean property to your ItemViewModel, and bind to it in a Style Setter for the TreeViewItem.
Add a SelectedItem property to your ViewModel used as the DataContext for the TreeView. This is the missing piece in the solution above.
' ItemVM...
Public Property IsSelected As Boolean
Get
Return _func.SelectedNode Is Me
End Get
Set(value As Boolean)
If IsSelected value Then
_func.SelectedNode = If(value, Me, Nothing)
End If
RaisePropertyChange()
End Set
End Property
' TreeVM...
Public Property SelectedItem As ItemVM
Get
Return _selectedItem
End Get
Set(value As ItemVM)
If _selectedItem Is value Then
Return
End If
Dim prev = _selectedItem
_selectedItem = value
If prev IsNot Nothing Then
prev.IsSelected = False
End If
If _selectedItem IsNot Nothing Then
_selectedItem.IsSelected = True
End If
End Set
End Property
<TreeView ItemsSource="{Binding Path=TreeVM}"
BorderBrush="Transparent">
<TreeView.ItemContainerStyle>
<Style TargetType="TreeViewItem">
<Setter Property="IsExpanded" Value="{Binding IsExpanded}"/>
<Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}"/>
</Style>
</TreeView.ItemContainerStyle>
<TreeView.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding Children}">
<TextBlock Text="{Binding Name}"/>
</HierarchicalDataTemplate>
</TreeView.ItemTemplate>
</TreeView>

After studying the Internet for a day I found my own solution for selecting an item after create a normal treeview in a normal WPF/C# environment
private void BuildSortTree(int sel)
{
MergeSort.Items.Clear();
TreeViewItem itTemp = new TreeViewItem();
itTemp.Header = SortList[0];
MergeSort.Items.Add(itTemp);
TreeViewItem prev;
itTemp.IsExpanded = true;
if (0 == sel) itTemp.IsSelected= true;
prev = itTemp;
for(int i = 1; i<SortList.Count; i++)
{
TreeViewItem itTempNEW = new TreeViewItem();
itTempNEW.Header = SortList[i];
prev.Items.Add(itTempNEW);
itTempNEW.IsExpanded = true;
if (i == sel) itTempNEW.IsSelected = true;
prev = itTempNEW ;
}
}

It can also be done using the IsSelected property of the TreeView item. Here's how I managed it,
public delegate void TreeviewItemSelectedHandler(TreeViewItem item);
public class TreeViewItem
{
public static event TreeviewItemSelectedHandler OnItemSelected = delegate { };
public bool IsSelected
{
get { return isSelected; }
set
{
isSelected = value;
if (value)
OnItemSelected(this);
}
}
}
Then in the ViewModel that contains the data your TreeView is bound to, just subscribe to the event in the TreeViewItem class.
TreeViewItem.OnItemSelected += TreeViewItemSelected;
And finally, implement this handler in the same ViewModel,
private void TreeViewItemSelected(TreeViewItem item)
{
//Do something
}
And the binding of course,
<Setter Property="IsSelected" Value="{Binding IsSelected}" />

I know this thread is 10 years old but the problem still exists....
The original question was 'to retrieve' the selected item. I also needed to "get" the selected item in my viewmodel (not set it). Of all the answers in this thread, the one by 'Wes' is the only one that approaches the problem differently: If you can use the 'Selected Item' as a target for databinding use it as a source for databinding. Wes did it to another view property, I will do it to a viewmodel property:
We need two things:
Create a dependency property in the viewmodel (in my case of type 'MyObject' as my treeview is bound to object of the 'MyObject' type)
Bind from the Treeview.SelectedItem to this property in the View's constructor (yes that is code behind but, it's likely that you will init your datacontext there as well)
Viewmodel:
public static readonly DependencyProperty SelectedTreeViewItemProperty = DependencyProperty.Register("SelectedTreeViewItem", typeof(MyObject), typeof(MyViewModel), new PropertyMetadata(OnSelectedTreeViewItemChanged));
private static void OnSelectedTreeViewItemChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
(d as MyViewModel).OnSelectedTreeViewItemChanged(e);
}
private void OnSelectedTreeViewItemChanged(DependencyPropertyChangedEventArgs e)
{
//do your stuff here
}
public MyObject SelectedWorkOrderTreeViewItem
{
get { return (MyObject)GetValue(SelectedTreeViewItemProperty); }
set { SetValue(SelectedTreeViewItemProperty, value); }
}
View constructor:
Binding binding = new Binding("SelectedItem")
{
Source = treeView, //name of tree view in xaml
Mode = BindingMode.OneWay
};
BindingOperations.SetBinding(DataContext, MyViewModel.SelectedTreeViewItemProperty, binding);

I propose this solution (which I consider the easiest and memory leaks free) which works perfectly for updating the ViewModel's selected item from the View's selected item.
Please note that changing the selected item from the ViewModel won't update the selected item of the View.
public class TreeViewEx : TreeView
{
public static readonly DependencyProperty SelectedItemExProperty = DependencyProperty.Register("SelectedItemEx", typeof(object), typeof(TreeViewEx), new FrameworkPropertyMetadata(default(object))
{
BindsTwoWayByDefault = true // Required in order to avoid setting the "BindingMode" from the XAML
});
public object SelectedItemEx
{
get => GetValue(SelectedItemExProperty);
set => SetValue(SelectedItemExProperty, value);
}
protected override void OnSelectedItemChanged(RoutedPropertyChangedEventArgs<object> e)
{
SelectedItemEx = e.NewValue;
}
}
XAML usage
<l:TreeViewEx ItemsSource="{Binding Path=Items}" SelectedItemEx="{Binding Path=SelectedItem}" >

(Let's just all agree that TreeView is obviously busted in respect to this problem. Binding to SelectedItem would have been obvious. Sigh)
I needed the solution to interact properly with the IsSelected property of TreeViewItem, so here's how I did it:
// the Type CustomThing needs to implement IsSelected with notification
// for this to work.
public class CustomTreeView : TreeView
{
public CustomThing SelectedCustomThing
{
get
{
return (CustomThing)GetValue(SelectedNode_Property);
}
set
{
SetValue(SelectedNode_Property, value);
if(value != null) value.IsSelected = true;
}
}
public static DependencyProperty SelectedNode_Property =
DependencyProperty.Register(
"SelectedCustomThing",
typeof(CustomThing),
typeof(CustomTreeView),
new FrameworkPropertyMetadata(
null,
FrameworkPropertyMetadataOptions.None,
SelectedNodeChanged));
public CustomTreeView(): base()
{
this.SelectedItemChanged += new RoutedPropertyChangedEventHandler<object>(SelectedItemChanged_CustomHandler);
}
void SelectedItemChanged_CustomHandler(object sender, RoutedPropertyChangedEventArgs<object> e)
{
SetValue(SelectedNode_Property, SelectedItem);
}
private static void SelectedNodeChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var treeView = d as CustomTreeView;
var newNode = e.NewValue as CustomThing;
treeView.SelectedCustomThing = (CustomThing)e.NewValue;
}
}
With this XAML:
<local:CustonTreeView ItemsSource="{Binding TreeRoot}"
SelectedCustomThing="{Binding SelectedNode,Mode=TwoWay}">
<TreeView.ItemContainerStyle>
<Style TargetType="TreeViewItem">
<Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}" />
</Style>
</TreeView.ItemContainerStyle>
</local:CustonTreeView>

I bring you my solution which offers the following features:
Supports 2 ways binding
Auto updates the TreeViewItem.IsSelected properties (according to the SelectedItem)
No TreeView subclassing
Items bound to ViewModel can be of any type (even null)
1/ Paste the following code in your CS:
public class BindableSelectedItem
{
public static readonly DependencyProperty SelectedItemProperty = DependencyProperty.RegisterAttached(
"SelectedItem", typeof(object), typeof(BindableSelectedItem), new PropertyMetadata(default(object), OnSelectedItemPropertyChangedCallback));
private static void OnSelectedItemPropertyChangedCallback(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var treeView = d as TreeView;
if (treeView != null)
{
BrowseTreeViewItems(treeView, tvi =>
{
tvi.IsSelected = tvi.DataContext == e.NewValue;
});
}
else
{
throw new Exception("Attached property supports only TreeView");
}
}
public static void SetSelectedItem(DependencyObject element, object value)
{
element.SetValue(SelectedItemProperty, value);
}
public static object GetSelectedItem(DependencyObject element)
{
return element.GetValue(SelectedItemProperty);
}
public static void BrowseTreeViewItems(TreeView treeView, Action<TreeViewItem> onBrowsedTreeViewItem)
{
var collectionsToVisit = new System.Collections.Generic.List<Tuple<ItemContainerGenerator, ItemCollection>> { new Tuple<ItemContainerGenerator, ItemCollection>(treeView.ItemContainerGenerator, treeView.Items) };
var collectionIndex = 0;
while (collectionIndex < collectionsToVisit.Count)
{
var itemContainerGenerator = collectionsToVisit[collectionIndex].Item1;
var itemCollection = collectionsToVisit[collectionIndex].Item2;
for (var i = 0; i < itemCollection.Count; i++)
{
var tvi = itemContainerGenerator.ContainerFromIndex(i) as TreeViewItem;
if (tvi == null)
{
continue;
}
if (tvi.ItemContainerGenerator.Status == System.Windows.Controls.Primitives.GeneratorStatus.ContainersGenerated)
{
collectionsToVisit.Add(new Tuple<ItemContainerGenerator, ItemCollection>(tvi.ItemContainerGenerator, tvi.Items));
}
onBrowsedTreeViewItem(tvi);
}
collectionIndex++;
}
}
}
2/ Example of use in your XAML file
<TreeView myNS:BindableSelectedItem.SelectedItem="{Binding Path=SelectedItem, Mode=TwoWay}" />

When clicking on some item list you'll get the data in "Selected" property.
ViewModel:
public class ShellViewModel : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
protected void NotifyPropertyChanged(String info)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(info));
}
}
private ObservableCollection<Books> _books;
private List<Books> bookList = new List<Books>();
public ObservableCollection<Books> Books
{
get { return _books; }
set { _books = value; NotifyPropertyChanged("Books"); }
}
private Books books;
public Books Selected
{
get { return books; }
set { books = value; }
}
public ShellViewModel()
{
bookList = new List<Books>()
{
new Books{BookName = "Harry Poter",Price ="15$"},
new Books{BookName = "Harry Poter 2 ",Price ="14.95$"},
new Books{BookName = "Harry Poter 3",Price ="18.50$"},
new Books{BookName = "Harry Poter 4",Price ="32.90$"},
};
Books = new ObservableCollection<Books>(bookList);
}
}
public class Books
{
public string BookName { get; set; }
public string Price { get; set; }
}
XAML:
<ListView x:Name="lst" Grid.Row="2" ItemsSource="{Binding Books}" SelectedItem="{Binding Selected}">
<ListView.View>
<GridView >
<GridViewColumn Header="Name" DisplayMemberBinding="{Binding BookName}" />
<GridViewColumn Header="Price" Width="100" DisplayMemberBinding="{Binding Price}"/>
</GridView>
</ListView.View>
</ListView>

I realise it's been a while since this was posted, but FWIW I'm using Telerik's RadTreeView, and SelectedItem seems to work fine - either the problem has been fixed in the meantime, or Telerik have worked round it for us.