System.Object
   Microsoft.UI.Xaml.DependencyObject
      Microsoft.UI.Xaml.UIElement
         Microsoft.UI.Xaml.FrameworkElement
            Microsoft.UI.Xaml.Controls.Control
               C1.WinUI.Core.C1View
                  C1.WinUI.Core.C1Border
                     C1.WinUI.Input.C1PopupBorder
                  C1.WinUI.Input.C1NumericBox
                  C1.WinUI.Input.C1ValidationDecorator
               C1.WinUI.Input.C1RangeSlider
               Microsoft.UI.Xaml.Controls.TextBox
                  C1.WinUI.Input.C1TextBoxBase
                     C1.WinUI.Input.C1TextBox
                        C1.WinUI.Input.C1MaskedTextBox
   System.EventArgs
      C1.WinUI.Core.AsyncEventArgs
         C1.WinUI.Input.TextBoxAutoCompleteEventArgs
      C1.WinUI.Input.MaskedTextChangedEventArgs
   System.ValueType
      C1.WinUI.Input.AnchorMatching

Reference

C1.WinUI.Input Assembly