The RibbonGalleryControl class encapsulates the ribbon gallery controls.

Autodesk.AutoCAD.Customization.IImageContainer
    Autodesk.AutoCAD.Customization.RibbonControl
        Autodesk.AutoCAD.Customization.RibbonGalleryControl

Public Class RibbonGalleryControl
Inherits RibbonControl
Inherits IImageContainer

public class RibbonGalleryControl : RibbonControl, IImageContainer;