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IOleInPlaceObjectWindowless interface

Enables a windowless object to process window messages and participate in drag and drop operations. It is derived from and extends the IOleInPlaceObject interface.

A small object, such as a control, does not need a window of its own. Instead, it can rely on its container to dispatch window messages and help the object to participate in drag and drop operations. The container must implement the IOleInPlaceSiteWindowless interface. Otherwise, the object must act as a normal compound document object and create a window when it is activated.

When to implement

Implement this interface on an object that can be in place activated without a window. This interface is derived from IOleInPlaceObject which, in turn, is derived from IOleWindow.

When to use

A container calls the methods in this interface to dispatch window messages to an in-place-active windowless object and to assist the object in participating in drag and drop operations. The container must implement a site object with the IOleInPlaceSiteWindowless interface to support these activities. See the IOleInPlaceSiteWindowless interface for more information on operations involving windowless objects, such as drawing, drag and drop, and processing window messages.


The IOleInPlaceObjectWindowless interface inherits from IOleInPlaceObject. IOleInPlaceObjectWindowless also has these types of members:


The IOleInPlaceObjectWindowless interface has these methods.


Retrieves the IDropTarget interface for an in-place active, windowless object that supports drag and drop.


Dispatches a message from a container to a windowless object that is in-place active.



Minimum supported client

Windows 2000 Professional [desktop apps only]

Minimum supported server

Windows 2000 Server [desktop apps only]






IID_IOleInPlaceObjectWindowless is defined as 1C2056CC-5EF4-101B-8BC8-00AA003E3B29

See also




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