Working with TAPI 3.x from .NET

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Introduction

Here I will post a class containing the event handling part in TAPI 3.0 and VB.NET.
I will also include the full project as a download.

The code is self explaining and well commented and if you need any further information, please drop me a PM.

All comments are welcome and please vote for the article.

Here is the full commented source code in VB.NET and I will be posting more in-depth tutorials about TAPI.

Imports TAPI3Lib 

Namespace VBCity.TAPI 

    Public Class VBTAPI 

        Private Const MediaAudio As Integer = 8 
        Private Const MediaModem As Integer = 16 
        Private Const MediaFax As Integer = 32 
        Private Const MediaVideo As Integer = 32768 

        Private WithEvents oTAPI As TAPI3Lib.TAPI ' will hold our TAPI object 
        ' will hold our selected address (you can hold many addresses in an array)
        Private oAddress As ITAddress 
        Private RegCookie As Integer 

        Sub New() 
            Try 
                ' creating a new instance to first initialize TAPI 
                ' before attaching the events 
                Dim m_TAPI As New TAPIClass 
                ' a variable to hold supported media types for the address 
                Dim MediaTypes As Integer 
                ' initializing TAPI 
                m_TAPI.Initialize() 
                ' attaching event sink 
                oTAPI = m_TAPI 
                ' getting rid of the private instance as we have another 
                ' global instance (oTAPI) 
                m_TAPI = Nothing 
                Dim AddressCollection As ITCollection = oTAPI.Addresses() 
                ' looping through address collection
                For Each Address As ITAddress In AddressCollection  
                    ' checking if address is working
                    If Address.State = ADDRESS_STATE.AS_INSERVICE Then  
                        ' extracting media support interface from the address 
                        Dim MediaSupport As ITMediaSupport = Address 
                        ' extracting media types supporting 
                        MediaTypes = MediaSupport.MediaTypes 
                        MediaSupport = Nothing ' dispose of the object 
                        If (MediaTypes And MediaModem) = MediaModem Then 
                            ' the address is a data Modem 
                            If (MediaTypes And MediaAudio) = MediaAudio Then 
                                ' Select the address since it supports Audio 
                                ' and is a FAX/Modem 
                                oAddress = Address ' select this address 
                                ' show the selected address name
                                MsgBox("we have selected this address: " + _
                                       oAddress.AddressName)  
                                Exit For 
                            End If 
                        End If 
                    End If 
                Next Address 
                If Not (oAddress Is Nothing) Then 
                    ' registering notifications for the selected address 
                    RegCookie = oTAPI.RegisterCallNotifications_
                                (oAddress, True, False, MediaTypes, 1) 
                    ' Note: this registration can be done on 
                    ' as many addresses as you want 
                    ' we will not receive notifications unless we specify 
                    ' which type of events we are interested in 
                    oTAPI.EventFilter = (TAPI_EVENT.TE_CALLNOTIFICATION Or _
                            TAPI_EVENT.TE_CALLSTATE Or TAPI_EVENT.TE_CALLINFOCHANGE) 
                Else 
                    MsgBox("no address selected") 
                End If 
            Catch ex As Exception 
                MsgBox("Error occurred:" & vbCrLf & ex.Message, _
                        MsgBoxStyle.Critical, "VBCITY.VBTAPI") 
            End Try 
            ' by now we are done for the initialization and registration 
            ' and the events should fire 
            ' Note: you must dispose of TAPI before you destroy the class 
            ' and I will leave this for now 
        End Sub 
        
        Private Sub oTAPI_Event(ByVal TapiEvent As TAPI3Lib.TAPI_EVENT, _
                        ByVal pEvent As Object) Handles oTAPI.Event 
            ' making a thread asynchronously process the event 
            Dim thAsyncCall As System.Threading.Thread 
            Select Case TapiEvent 
            
                Case TAPI_EVENT.TE_CALLNOTIFICATION 'Call Notification Arrived 
                    ' assigning our sub's delegate to the thread 
                    thAsyncCall = New Threading.Thread(AddressOf CallNotificationEvent) 
                    ' passing the variable for the thread 
                    CallNotificationObject = CType(pEvent, ITCallNotificationEvent) 
                    ' starting the thread 
                    thAsyncCall.Start() 
                    
                Case TAPI_EVENT.TE_CALLSTATE 'Call State Changes 
                    ' assigning our sub's delegate to the thread 
                    thAsyncCall = New Threading.Thread(AddressOf CallStateEvent) 
                    ' passing the variable for the thread 
                    CallStateObject = CType(pEvent, ITCallStateEvent) 
                    ' starting the thread 
                    thAsyncCall.Start() 
                    
                Case TAPI_EVENT.TE_CALLINFOCHANGE 'Call Info Changes 
                    ' assigning our sub's delegate to the thread 
                    thAsyncCall = New Threading.Thread(AddressOf CallInfoEvent) 
                    ' passing the variable for the thread 
                    CallInfoObject = CType(pEvent, ITCallInfoChangeEvent) 
                    ' starting the thread 
                    thAsyncCall.Start() 
                    
            End Select 
        End Sub 
        
        Private CallNotificationObject As ITCallNotificationEvent 
        Private Sub CallNotificationEvent() 
            ' here we should check to see various notifications of new and ended calls 
            Select Case CallNotificationObject.Event 
            
                Case CALL_NOTIFICATION_EVENT.CNE_MONITOR 
                    ' the notification is for a monitored call 
                Case CALL_NOTIFICATION_EVENT.CNE_OWNER 
                    ' the notification is for an owned call 
            
            End Select 
        End Sub 

        Private CallStateObject As ITCallStateEvent 
        Private Sub CallStateEvent() 
            ' here we should check to see call state and handle connects and disconnects 
            Select Case CallStateObject.State 
            
                Case CALL_STATE.CS_IDLE 
                Case CALL_STATE.CS_INPROGRESS 
                Case CALL_STATE.CS_OFFERING 
                    ' a call is offering so if you don't want it then pass it 
                    ' The code to pass the call is the following 
                    ' Dim CallControl As ITBasicCallControl = CallStateObject.Call 
                    ' CallControl.HandoffIndirect (CallStateObject.Call.CallInfoLong_
                                            (CALLINFO_LONG.CIL_MEDIATYPESAVAILABLE) 
                Case CALL_STATE.CS_CONNECTED 
                    ' call is connected 
                Case CALL_STATE.CS_QUEUED 
                    ' call is being queued 
                Case CALL_STATE.CS_HOLD 
                    ' call is on hold 
                Case CALL_STATE.CS_DISCONNECTED 
                    ' call is disconnected 
            
            End Select 
        End Sub 

        Private CallInfoObject As ITCallInfoChangeEvent 
        Private Sub CallInfoEvent() 
            ' here you can extract information from the call 
            ' the code to extract the caller ID 
            ' >>> put the following code in a try block and 
            ' swallow the exception if it gives errors 
            Dim CallerID As String 
            CallerID = CallInfoObject.Call.CallInfoString_
                    (CALLINFO_STRING.CIS_CALLERIDNAME) 
        End Sub 

    End Class 
End Namespace

History

• 7^th August, 2005: Initial post