` Printed Icetips Article

Icetips Article

Windows API: Handling events from COM in OLE class
2002-11-03 -- Jim Kane
 
Newsgroups: softvelocity.products.c55ee


The type library you sent me indicates the com object generates an event.
Cw does not natively support events used in conjunction with interfaces.
However I wrote an article for cw mag that included my conptcl (connection
point class) that does this in a thread-safe manor.
The iid for the one and only event interface according to ole view is:
IID:Icti32Events          group  !verify I copied correctly
data1               ulong(0F1a9c677H)
data2               ushort(03c8bH)
data3               ushort(04812H)
data4
string('<0b2H><0dbH><0dcH><02bH><0beH><080H><0acH><0aaH>')
  end
to use my class and receive the event, create a window with an acceptloop.
I'll call the window structure eventwindow.
Call my conptcl init method like this in the event:openwindow:
event:oleevent equate(9ABH) !arbitrary
uniqueString equate('cticomobject') !arbitrary
parametercount long
eventid long
parameterarray like(vartype),dim(15)

  !set up to connect for events later
  if SELF.ConPtCl.init(EventWindow, event:oleevent, thread(), uniquestring)
then
    message('Error cant get events.')
    post(event:closewindow)
  end
 !lpinterface is the address of the interface you have been calling
 !we use that interfaces queryinterface() method to ask about events
 !the connection point interfaces we get back from queryinteface allow us to
register to receive the events.
  if SELF.conptcl.connect(SELF.lpInterface, address(IID:Icti32Events)) then
    SELF.TakeError('connecting to cti object failed - no events')
    post(event:closewindow)
  end
in event:closewindow
  conptcl.unadvise()
in event:oleevent
      loop
        if SELF.ConptCl.GetNextEvent(EventId, parametercount,
Address(parameterArray)) then break.
        !eventid will always be 1 and parameter count 0.  parameterarray is
unused
        !display/process the event
        yourclass.gotevent()
     end

now your class gets called when ever the event fires.  I thought It was odd
that they dont pass the the id to tell you which line but for what ever
reason according to ole view they do not.  I suspect you should only call
setcallback for one line if you are relying on events.

Jim Kane







ddock"  wrote in message
news:3dc55e5b$1@news.softvelocity.com...
> Well one of the options when starting it is to create a log, so I did
that.
> Here's a clip from it:
>
> 11-03 9:27:49.150 Received Event on device 1 - Event: 134
> 11-03 9:27:49.150 dxxxB1C4: EVENT Ring.
> 11-03 9:27:49.150 Fired callback for dxxxB1C4
>
> So it does detect a ring and 'fire a callback' ... If I knew how to trap
> either event, the ring detect or firing the callback, I could do I what I
> need to but I don't know how to do that. The parameters I stated earlier
are
> the only ones I can pass ... no place to hand it the address of a
procedure
> to handle the callback.
>
> Ideas?
>
> "John E. Christ III"  wrote in message
> news:3dc54ee3$1@news.softvelocity.com...
> > > I don't know how the connection between the event firing
> > > and the callback routine is made.
> >
> > I would expect that you would tell it where to find your callback
> procedure,
> > and then it would call that procedure when the event occurs.  But that's
> > just a guess based on what you've said.
> >
> > John
> >
> >
>
>

Printed November 23, 2024, 8:23 pm
This article has been viewed/printed 35206 times.
Google search has resulted in 45 hits on this article since January 25, 2004.