This wraps the ObjectARX AcDbAssocVertexActionParam class.

Autodesk.AutoCAD.DatabaseServices.DBObject
    Autodesk.AutoCAD.DatabaseServices.AssocActionParam
        Autodesk.AutoCAD.DatabaseServices.AssocVertexActionParam

Public Class AssocVertexActionParam
Inherits AssocActionParam

public class AssocVertexActionParam : AssocActionParam;