An instance of the MdoDesigner class represents a Visual Basic custom base class in the repository.
| Interface | Description |
| IMdoComponent | Maintains the relationship between a Visual Basic component and the Visual Basic project to which it belongs. |
| IMdoModelItem | Maintains properties that are common to many different types of MDO Model objects. |
| IRepositoryItem | Manages repository objects and relationships. |
| IRepositoryObject | Retrieves repository object identifiers. |
| IRepositoryObjectStorage | Creates and loads repository objects. |