Data binding to 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

Answer 1

WPF MVVM TreeView SelectedItem

... is a better answer, but does not mention a way to get/set the SelectedItem in the ViewModel.

1. Add a IsSelected boolean property to your ItemViewModel, and bind to it in a Style Setter for the TreeViewItem.
2. 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