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Attribute VB_Name = "RasNotification" |
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' from: http://www.pscode.com/vb/scripts/ShowCode.asp?txtCodeId=34927&lngWId=1 |
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Option Explicit |
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Public Const RASCN_Connection = &H1 'Our two flags |
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Public Const RASCN_Disconnection = &H2 |
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Public Const WAIT_FAILED = &HFFFFFFFF |
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Public Const WAIT_OBJECT_0 = &H0& |
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Public Const WAIT_ABANDONED = &H80& |
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Public Const WAIT_TIMEOUT = &H102& |
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Public Type SECURITY_ATTRIBUTES |
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nLength As Long |
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lpSecurityDescriptor As Long |
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bInheritHandle As Long |
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End Type |
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Public Declare Function CreateEvent Lib "kernel32" Alias "CreateEventA" (lpEventAttributes As SECURITY_ATTRIBUTES, ByVal bManualReset As Long, ByVal bInitialState As Long, ByVal lpName As String) As Long |
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Public Declare Function RasConnectionNotification Lib "rasapi32.dll" Alias "RasConnectionNotificationA" (hRasConn As Long, ByVal hEvent As Long, ByVal dwFlags As Long) As Long |
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Public Declare Function WaitForMultipleObjects Lib "kernel32" (ByVal nCount As Long, lpHandles As Long, ByVal bWaitAll As Long, ByVal dwMilliseconds As Long) As Long |
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Public Declare Function ResetEvent Lib "kernel32" (ByVal hEvent As Long) As Long |
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Public Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long |
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Public Sub MonitorRASStatusAsync() |
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Dim hEvents(1) As Long 'Array of event handles. Since there are ' two events we'd like to monitor, i have already dimention it. |
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Dim RasNotif As Long |
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Dim WaitRet As Long |
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Dim sd As SECURITY_ATTRIBUTES |
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Dim hRasConn As Long |
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Dim thrownEvent As EventInfo |
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hRasConn = 0 |
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'We are going to create and register two event objects with CreateEvent API function |
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'There aren't any special treated events that need any kind of security attributes so we just initialize the structure |
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With sd |
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.nLength = Len(sd) 'we pass the length of sd |
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.lpSecurityDescriptor = 0 |
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.bInheritHandle = 0 |
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End With |
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'We create the event by passing in CreateEvent any security attributes, |
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'we want to manually reset the event after it gets signaled, |
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'we also want it's initial state not signaled assuming that we don't have yet any connection to the internet, |
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'last but not least we give the event a name (RASStatusNotificationObject1) |
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hEvents(0) = CreateEvent(sd, True, False, "RASStatusNotificationObject1") |
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'If the returned value was zero, something went wrong so exit the sub |
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If hEvents(0) = 0 Then MsgBox "Couldn't assign an event handle": Exit Sub |
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'If we succesfully created the first event object we pass it to RasConnectionNotification |
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'with the flag RASCN_Connection so that this event will monitor for internet connection |
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RasNotif = RasConnectionNotification(ByVal hRasConn, hEvents(0), RASCN_Connection) |
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If RasNotif <> 0 Then MsgBox "Ras Notification failure": GoTo ras_TerminateEvent |
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'We create the second event object exactly like the first one |
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'but we name it RASStatusNotificationObject2 |
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hEvents(1) = CreateEvent(sd, True, False, "RASStatusNotificationObject2") |
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If hEvents(1) = 0 Then MsgBox "Couldn't assign an event handle": Exit Sub |
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'If we succesfully created the second event object too, we pass it to RasConnectionNotification |
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'with the flag RASCN_Disconnection. This event will monitor for disconnection |
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RasNotif = RasConnectionNotification(ByVal hRasConn, hEvents(1), RASCN_Disconnection) |
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If RasNotif <> 0 Then MsgBox "Ras Notification failure": GoTo ras_TerminateEvent |
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'We then issue the loop |
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'Notice that we have put hEvents array to it's first array item. |
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'and we used False cause we want to get notifications |
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'when any of the two events occur. |
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Do |
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WaitRet = WaitForMultipleObjects(2, hEvents(0), False, 20) |
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Select Case WaitRet |
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Case WAIT_TIMEOUT |
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DoEvents |
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Case WAIT_FAILED Or WAIT_ABANDONED Or WAIT_ABANDONED + 1 |
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GoTo ras_TerminateEvent |
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Case WAIT_OBJECT_0 |
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'MsgBox "Connected" |
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'MsgBox hEvents(0) |
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'thrownEvent = hEvents(0) |
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'MsgBox thrownEvent.Name |
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detectOnlineOfflineChange |
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ResetEvent hEvents(0) 'Reset the event to avoid a second message box |
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DoEvents 'Free any pending messages |
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Case WAIT_OBJECT_0 + 1 |
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'MsgBox "Disconnected" |
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detectOnlineOfflineChange |
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ResetEvent hEvents(1) 'Reset the event to place it in no signal state (Manual reset, remember?) |
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DoEvents |
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End Select |
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Loop |
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ras_TerminateEvent: |
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'Close all event handles |
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'For more than two events you could apply a For.. Next |
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Call CloseHandle(hEvents(1)) |
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Call CloseHandle(hEvents(0)) |
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DoEvents 'Free any pending messages from the application message queue |
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End Sub |
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