System.Object
   OPCDA.NET.ItemDef
   OPCDA.NET.ItemIdentification
      OPCDA.NET.ItemValue
   OPCDA.NET.ItemProperties
   OPCDA.NET.ItemPropertyData
   OPCDA.NET.ItemPropertyItemID
   OPCDA.NET.OPCItemAttributes
   OPCDA.NET.OPCItemDef
   OPCDA.NET.OPCItemProperty
   OPCDA.NET.OPCItemResult
   OPCDA.NET.OPCItemState
   OPCDA.NET.OPCWriteResult
   OPCDA.NET.Property
   OPCDA.NET.SetStateArgs
   OPCDA.NET.StandardProperties
   System.EventArgs
      OPCDA.NET.CancelCompleteEventArgs
      OPCDA.NET.DataChangeEventArgs
      OPCDA.NET.ReadCompleteEventArgs
      OPCDA.NET.WriteCompleteEventArgs

Reference

OpcNetBase.Net4 Assembly