IAccessibleWindowlessSite interface (oleacc.h)

A Microsoft ActiveX control site implements this interface to enable a windowless ActiveX control that has a Microsoft Active Accessibility implementation to express its accessibility. This interface enables the control container to reserve a range of object IDs that a windowless control can use to raise events, and enables the control container to provide an IAccessible pointer for the parent of the windowless control.


The IAccessibleWindowlessSite interface inherits from the IUnknown interface. IAccessibleWindowlessSite also has these types of members:


The IAccessibleWindowlessSite interface has these methods.


Acquires a range of object IDs from the control host and marks them as reserved by a specific windowless control.

Retrieves an IAccessible pointer for the parent of a windowless Microsoft ActiveX control in the accessibility tree.

Retrieves the object ID ranges that a particular windowless Microsoft ActiveX control has reserved.

Releases an object ID range that was acquired by a previous call to the IAccessibleWindowlessSite::AcquireObjectIdRange method.


The functions that manage object ID ranges expect the site object to maintain a list of ranges that have already been reserved. When the window that contains the ActiveX control receives a WM_GETOBJECT message with an LPARAM value (object ID) that is in a reserved range, the window should call the IAccessibleHandler::AccessibleObjectFromID method to get an IAccessible object for that object ID.


Minimum supported client Windows 8 [desktop apps only]
Minimum supported server Windows Server 2012 [desktop apps only]
Target Platform Windows
Header oleacc.h

See also