public event EventHandler<RadRoutedEventArgs> PreviewUnselected

Public Event PreviewUnselected As EventHandler(Of RadRoutedEventArgs)

void private void RadTreeView1_PreviewUnselected(object sender, RadRoutedEventArgs e)
{
    // get a reference to the item that will be unselected
    RadTreeViewItem itemToUnselect = e.Source as RadTreeViewItem;

    // if the action should be canceled set Handled property to true
    e.Handled = true;
}

No code example is currently available or this language may not be supported.

<telerik:RadTreeView 
    x:Name="RadTreeView1" 
    PreviewUnselected="RadTreeView1_PreviewUnselected"/>