What are the different classes used in Visual tree?

Answer

The different classes that are used in Visual tree are as follows:
ScrollViewer: allows to include an area that is scrollable and contains the visible elements of it like scroll bar.
ScrollContentPresenter: allows the content of the ScrollViewer to be displayed.
ItemsPresenter: allows the control of the specific item to be used in a visual tree where it present the items that has to be arranged in a panel using ItemsPanel and ItemsControl.

VirtualizingStackPanel: this arranges the stack panel and virtualizes the content used in it in a single line that can be made oriented in any direction either horizontal or vertical.
ContentPresenter: allows the user to present and displays the content of a ContentControl method. It also allows the flow of the content to be managed together in one way and can be represented together.