SelectedItem in a WPF Treeview

Question

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;
}

Answer 1

This property exists : TreeView.SelectedItem

But it is readonly, so you cannot assign it through a binding, only retrieve it

Answer 2

You might also be able to use TreeViewItem.IsSelected property

Answer 3

well, I find a solution, it move the mess, so 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 yor xmla

 <local:ExtendedTreeView ItemsSource="{Binding Items}" SelectedItem_="{Binding Item, Mode=TwoWay}">
 .....
 </local:ExtendedTreeView>