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<!DOCTYPE concept

  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">

<concept id="GUID-6A2160F0-6062-4E77-ABA3-B829AF9689FA" xml:lang="en"><title>Contacts

database events</title><prolog><metadata><keywords/></metadata></prolog><conbody>

<p>A client application of the Contacts Server can be set to observe changes

in the contacts database. When a change in the database occurs, the application

gets an event. The event carries information about the type of the event,

the contact ID, and the connection ID.</p>

<codeblock id="GUID-F552F563-6AA7-4E55-9E0E-F131E2B2C91B" xml:space="preserve">struct TContactDbObserverEvent

    {

    TContactDbObserverEventType iType;

    TContactItemId iContactId;

    TUint iConnectionId;

    };

</codeblock>

<p>The following event types are defined in the <parmname>cntdbobs.h</parmname> header:</p>

<codeblock id="GUID-9022E0A5-8CF3-469E-B1D4-2B2CC607F852" xml:space="preserve">enum TContactDbObserverEventType

    {

    EContactDbObserverEventNull,

    EContactDbObserverEventUnused,

    EContactDbObserverEventContactChanged,

    EContactDbObserverEventContactDeleted,

    EContactDbObserverEventContactAdded,

    EContactDbObserverEventUnknownChanges,

    EContactDbObserverEventRecover,

    EContactDbObserverEventRollback,

    EContactDbObserverEventTablesClosed,

    EContactDbObserverEventTablesOpened,

    EContactDbObserverEventTemplateChanged,

    EContactDbObserverEventTemplateDeleted,

    EContactDbObserverEventTemplateAdded,

    EContactDbObserverEventCurrentItemDeleted,

    EContactDbObserverEventCurrentItemChanged,

    EContactDbObserverEventOwnCardChanged,

    EContactDbObserverEventPreferredTemplateChanged,

    EContactDbObserverEventOwnCardDeleted,

    EContactDbObserverEventGroupAdded,

    EContactDbObserverEventGroupChanged,

    EContactDbObserverEventGroupDeleted,

    EContactDbObserverEventCurrentDatabaseChanged,

    EContactDbObserverEventSpeedDialsChanged

    EContactDbObserverEventSortOrderChanged,

    EContactDbObserverEventBackupBeginning,

    EContactDbObserverEventRestoreBeginning,

    EContactDbObserverEventBackupRestoreCompleted,

    EContactDbObserverEventRestoreBadDatabase,

    };

</codeblock>

<p>In order to make an application receive events about contact database

changes, the <xref href="jar:GUID-35228542-8C95-4849-A73F-2B4F082F0C44.jar!/sdk/doc_source/reference/reference-cpp/CNTMODEL/MContactDbObserverClass.html#%3a%3aMContactDbObserver" format="application/java-archive"><parmname>MContactDbObserver</parmname></xref> base class must be inherited and <xref href="jar:GUID-35228542-8C95-4849-A73F-2B4F082F0C44.jar!/sdk/doc_source/reference/reference-cpp/CNTMODEL/MContactDbObserverClass.html#%3a%3aMContactDbObserver%3a%3aHandleDatabaseEventL%28%29" format="application/java-archive"><parmname>HandleDatabaseEventL()</parmname></xref> virtual function must be implemented.

The function is called by the system when a contact database event occurs.</p>

<codeblock id="GUID-EEB33DFB-0009-4CE5-BC96-41B65519F8D1" xml:space="preserve">class CMyContactObserver : public CBase, public MContactDbObserver

    {

     public:

         // any public data and functions

         CMyContactObserver ();

         // override the virtual function from the base class

         virtual void HandleDatabaseEventL( TContactDbObserverEvent aEvent );

         };

     // handling contact database events

     void CMyContactObserver::HandleDatabaseEventL( TContactDbObserverEvent aEvent )

         {

         // Event handling code

         }

</codeblock>

<p>In addition, the application must create the <xref href="jar:GUID-35228542-8C95-4849-A73F-2B4F082F0C44.jar!/sdk/doc_source/reference/reference-cpp/CNTMODEL/CContactChangeNotifierClass.html#%3a%3aCContactChangeNotifier" format="application/java-archive"><parmname>CContactChangeNotifier</parmname></xref> object to register itself to receive events.</p>

<codeblock id="GUID-95A974D8-3D88-4E64-8A33-AF2366C34791" xml:space="preserve">CContactDatabase* contactDb = CContactDatabase::OpenL();

//iContactDbObserver is a CMyContactObserver pointer

CContactChangeNotifier* notifier = CContactChangeNotifier::NewL( *contactDb, iContactDbObserver );

</codeblock>

</conbody></concept>