System.Object
   System.EventArgs
      C1.WPF.TreeView.AutoSearchBufferChangedEventArgs
      System.Windows.RoutedEventArgs
         System.Windows.Controls.SelectionChangedEventArgs
            C1.WPF.TreeView.SelectionChangingEventArgs
   System.Windows.Threading.DispatcherObject
      System.Windows.DependencyObject
         System.Windows.Media.Visual
            System.Windows.UIElement
               System.Windows.FrameworkElement
                  System.Windows.Controls.Control
                     C1.WPF.TreeView.C1TreeViewLine
                     System.Windows.Controls.ContentControl
                        System.Windows.Controls.Primitives.ButtonBase
                           System.Windows.Controls.Primitives.ToggleButton
                              C1.WPF.TreeView.C1TreeViewExpandButton
                     System.Windows.Controls.ItemsControl
                        C1.WPF.Core.C1ItemsControl
                           C1.WPF.Core.C1HierarchicalPresenter
                              C1.WPF.TreeView.C1TreeView
                              C1.WPF.TreeView.C1TreeViewItem
                  System.Windows.Controls.Panel
                     System.Windows.Controls.Canvas
                        C1.WPF.TreeView.C1TreeViewLinePanel
                     System.Windows.Controls.VirtualizingPanel
                        C1.WPF.TreeView.C1TreeViewPanel

Reference

C1.WPF.TreeView Assembly