# IOleInPlaceObjectWindowless

The 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.

Methods in VTable Order

IUnknown Methods | Description
QueryInterface | Returns a pointer to a specified interface.
AddRef | Increments the reference count.
Release | Decrements the reference count.

IOleWindow Methods | Description
GetWindow | Gets a window handle.
ContextSensitiveHelp | Controls enabling of context sensitive help.

IOleInPlaceObject Methods | Description
InPlaceDeactivate | Deactivate active in-place object.
UIDeactivate | Deactivate and remove UI of active object.
SetObjectRects | Portion of in-place object to be visible.
ReactivateAndUndo | Reactivate previously deactivated object.

IOleInPlaceObjectWindowless Methods | Description
OnWindowMessage | Dispatches a message from the container to a windowless object.
GetDropTarget | Supplies the IDropTarget interface for a windowless object that supports drag and drop.

See Also

IOleInPlaceSiteWindowless