Register Events

The following code snippets demonstrate implementation of a simple event handler, registration of the main TAPI event interface, setting of the event filter, and registration for call notifications.

Before using this code snippet, you must perform the operations in Initialize TAPI and Select an Address.

Note  This snippet does not have the error checking and releases appropriate for real code.

C++ Code Snippets [C++]

//
// Snippet 1: Implement a simple event handler.
//
HRESULT STDMETHODCALLTYPE
CTAPIEventNotification::Event(
    TAPI_EVENT  TapiEvent,
    IDispatch * pEvent
    )
{
    // AddRef the event so it doesn't go away.
    pEvent->AddRef();

    // Post a message to our own UI thread.
    PostMessage(
        ghDlg,
        WM_PRIVATETAPIEVENT,
        (WPARAM) TapiEvent,
        (LPARAM) pEvent
        );

    return S_OK;
}

//
// Snippet 2: Register the event interface.
//
ULONG                         gulAdvise;  // Globally declared
IConnectionPointContainer   * pCPC;
IConnectionPoint            * pCP;
ITTAPIEventNotification     * gpTAPIEventNotification;

gpTapi->QueryInterface(
     IID_IConnectionPointContainer,
     (void **)&pCPC
     );

pCPC->FindConnectionPoint(
     IID_ITTAPIEventNotification,
     &pCP
     );

pCPC->Release();

// Retain gulAdvise for future use
pCP->Advise(
     gpTAPIEventNotification,
     &gulAdvise
     );

pCP->Release();

//
// Snippet 3: Set the event filter.
//
// Assume we are interested
// only in call-related events.
gpTapi->put_EventFilter(
   TE_CALLNOTIFICATION | TE_CALLSTATE | TE_CALLMEDIA
   );

//
// Snippet 4: Register an address with TAPI
// for call notifications. Assume we are interested
// in video and audio calls, and that pAddress
// is a pointer to the ITAddress interface of
// an address that can handle both media types.

long glRegister; // Globally declared

gpTapi->RegisterCallNotifications(
    pAddress,
    VARIANT_TRUE,   // monitor privileges
    VARIANT_TRUE,   // owner privileges
    TAPIMEDIATYPE_AUDIO|TAPIMEDIATYPE_VIDEO,
    gulAdvise,      // As returned by Advise
    &glRegister
    );

Visual Basic Code Snippet [Visual Basic]

'Usually declared globally
Dim WithEvents gobjTapiWithEvents As TAPI
Attribute gobjTapiWithEvents.VB_VarHelpID = -1
Dim glRegistrationToken As Long

'Usually performed at the same time
'as TAPI initialization
Const TAPI3_CALL_EVENTS = _
    TE_CALLMEDIA Or _
    TE_CALLNOTIFICATION Or _
    TE_CALLSTATE

'Set the EventFilter to accept all defined TAPI events.
gobjTapi.EventFilter = TAPI3_CALL_EVENTS

'Register the outgoing interface (the one that will actually
'receive and process the events).
Set gobjTapiWithEvents = gobjTapi
Dim fOwner As Boolean, fMonitor As Boolean
Dim lMediaTypes As Long, lCallbackInstance As Long

'fOwner = True ensures that the application receives incoming calls
'and their call state events.
fOwner = True
fMonitor = False
lMediaTypes = TAPIMEDIATYPE_AUDIO
lCallbackInstance = 1

glRegistrationToken = gobjTapi.RegisterCallNotifications( _
    gobjAddress, _
    fMonitor, _
    fOwner, _
    lMediaTypes, _
    lCallbackInstance
    )

See Also

ITTAPIEventNotification::Event, TAPI_EVENT, ITTAPI::put_EventFilter, TAPIMEDIATYPE_ Constants, ITTAPI::RegisterCallNotifications