IOleObject

IOleObject is a COM interface used in the Object Linking and Embedding (OLE) framework to represent objects that can be embedded in or linked from a container application. It inherits from IUnknown and is typically implemented by either the embedded object or the host container to manage the lifecycle and interactions of the object within a document or window.

The interface provides a set of methods for container–object communications. SetClientSite and GetClientSite allow the object to communicate with its container through the IOleClientSite interface. SetHostNames and GetMoniker assist in identifying the container and the object. InitFromData and GetClipboardData enable data transfer, while DoVerb and EnumVerbs expose activation actions and the available verbs for user interaction. Update and IsUpToDate manage synchronization and caching. GetUserClassID and GetUserType support identification and presentation of the object. SetExtent and GetExtent specify the object's size, Close signals termination, and Advise/Unadvise/EnumAdvise provide change notification. GetMiscStatus returns miscellaneous status flags, and SetColorScheme relates to UI theming in certain scenarios.

IOleObject coordinates with other OLE interfaces, such as IOleInPlaceSite and IOleInPlaceObject, to enable in-place activation and editing. It serves as a central contract between containers and embedded or linked objects, underpinning embedding, linking, and in-place editing within host applications. The interface remains a foundational element in the OLE and COM ecosystems, notably in environments that host ActiveX controls and OCX components. Related interfaces include IOleClientSite, IMoniker, and IDataObject.