Platform SDK: MAPI |
The IMAPIFormAdviseSink::OnChange method indicates that a change has occurred in the status of the form viewer.
See IMAPIFormAdviseSink : IUnknown.
HRESULT OnChange( ULONG ulDir );
Form viewers call the IMAPIFormAdviseSink::OnChange method to notify the form about a change in a viewer's status. Usually, the only change is setting or clearing the VCSTATUS_NEXT or VCSTATUS_PREVIOUS flag based on the presence or absence of a next or previous message in the viewer. The form object then enables or disables any next or previous actions it supports accordingly.
The settings of VCSTATUS_MODAL and VCSTATUS_INTERACTIVE cannot change in a view context once it has been created.
The specific implementation of this method is entirely dependent on the specifics of your form. Most form objects use this method to alter their user interface — for example, enable or disable menu commands or buttons — to match the viewer status flags parameter.