IMAPIFormAdviseSink::OnChange
Applies to: Office 2010 | Outlook 2010 | Visual Studio
Indicates that a change has occurred in the status of the form viewer.
HRESULT OnChange(
ULONG ulDir
);
Parameters
ulDir
[in] A 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 Value
- 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. Accordingly, the form object then enables or disables any next or previous actions it supports.
The settings of VCSTATUS_MODAL and VCSTATUS_INTERACTIVE cannot change in a view context after it has been created.
Notes to Implementers
The specific implementation of this method is completely dependent on the specifics of the form. Most form objects use this method to change their user interface (for example, to enable or disable menu commands or buttons to match the viewer status flags parameter).