IMAPIFormAdviseSink::OnChange

The IMAPIFormAdviseSink::OnChange method indicates that a change has occurred in the status of the form viewer.

Quick Info

See IMAPIFormAdviseSink : IUnknown.

HRESULT OnChange(
  ULONG ulDir  
);
 

Parameters

ulDir

[in] Bitmask of flags that provides information about the change that has occurred in the viewer and the expected response in the form. The following flags can be set:

VCSTATUS_CATEGORY

There is a next or previous message in another category.

VCSTATUS_INTERACTIVE

The form should display a user interface. If this flag is not set, the form should suppress displaying a user interface even in response to a verb that usually causes a user interface to be displayed.

VCSTATUS_MODAL

The form is to be modal to the form viewer.

VCSTATUS_NEXT

There is a next message in the form viewer.

VCSTATUS_PREV

There is a previous message in the form viewer.

VCSTATUS_READONLY

Delete, submit, and move operations should be disabled.

VCSTATUS_UNREAD

There is a next or previous unread message in the form viewer.

Return Values

S_OK

The notification was successful.

Remarks

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.

Notes to Implementers

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.

See Also

IMAPIViewContext::ActivateNext