System.Object
   C1.Xamarin.Forms.Input.ComboBoxItemLoadingEventArgs
   System.EventArgs
      C1.Xamarin.Forms.Core.AsyncEventArgs
         C1.Xamarin.Forms.Input.AutoCompleteFilteringEventArgs
      C1.Xamarin.Forms.Input.CompletedEventArgs
      C1.Xamarin.Forms.Input.DropDownOpenChangedEventArgs
      C1.Xamarin.Forms.Input.DropDownOpenChangingEventArgs
      C1.Xamarin.Forms.Input.TextChangedEventArgs
   Xamarin.Forms.BindableObject
      Xamarin.Forms.Element
         Xamarin.Forms.VisualElement
            Xamarin.Forms.View
               Xamarin.Forms.InputView
                  Xamarin.Forms.Entry
                     C1.Xamarin.Forms.Input.C1MaskedEntry
               Xamarin.Forms.Layout
                  Xamarin.Forms.Layout<T>
                     C1.Xamarin.Forms.Input.C1DropDown
                        C1.Xamarin.Forms.Input.C1ComboBox
                           C1.Xamarin.Forms.Input.C1AutoComplete

Reference

C1.Xamarin.Forms.Input Assembly