I can not get LabVIEW to respond to a VB6 ActiveX event

[cueball]

I am working with a VB6 ActiveX dll (VBtablet.dll is a wrapper for Wintab32 for a tablet interface) using LV8.2.1 and can not get it to respond to an event.  I have opend the object and registered it for callback, but have had no luck in having an event generated.  Is there anyway to see these events generated or at least that it has been registered?  The dll has no problem working in a VB app or in Excel using a VB macro.  Is there anything special that has to be in the ActiveX object to get LabVIEW to respond to it?

When I register the callback I use a control reference of the data being returned as my "user data" and in the callback VI I wire the event data into the "Value" of the control reference. I believe this is all I have to do.  Any ideas would be helpfull.

Thanks,

Paul 

[Devin_K]

Paul,

I read over the description you provided, and it sounds like what you are doing should work, although sending in a control reference as to a callback VI is not something I've tried before.  If you haven't already, have a look at the "ActiveX Event Callback for Excel" example provided with LabVIEW, and compare it with your implementation to see if there is something simple that you might be missing. 

One thing you could try is to add a pop-up or something similar to your callback VI to verified whether it is being called.

[cueball]

I am able to see that events are generated from the dll, but somewhere between the ActiveX object and LabVIEW it is disconnected.  Is it possible that LabVIEW is excepting these events and not allowing then into the code.  The path as I see it is

dll -> WinAPI -> ActiveX -> LabVIEW

One thing this dll requires is a windows handle and I am wondering if LabVIEW itself is reads the events directly instead of ignoring them.  The reason I bring it up is that the tablet works like a mouse and I am wondering if it is absorbing these commands directly and not allowing them to be passed through the ActiveX object. Like this

dll-> WinAPI -> LabVIEW

therefore the event is never generated.  That is why I wish I could speak with someone at NI that could explain that process better, but it seems like there is no one at NI who knows any high level issues.

[Devin_K]

Paul,

I apologize, but I am not familiar with any special considerations needed when using a VB ActiveX DLL.  I tried looking around for someone who had attempted something similar, and came across a topic on the LAVA forums.  Have a look at it and maybe it will give you some additional insight:
http://forums.lavag.org/Callback-Event-VB6-Labview-t582.html

[JernejPerhavc]

Hi!

I am facing the same problem. I cannot get the VBtablet.dll to  work properly. I register for events, but none are posted. It has been a long time since this question has been posted, so I am wondering if anybody found any anwsers on how to make the VBtablet.dll to work?

Thank you

Jernej Perhavc

[Ipshita_C]

Please look at the LAVA forums as Devin had suggested.

Ipshita C.

[MichaelAivaliotis]

The suggested post has now been moved here: http://lavag.org/topic/1402-callback-event-vb6-labview/

[rolfk]

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cueball wrote:

I am able to see that events are generated from the dll, but somewhere between the ActiveX object and LabVIEW it is disconnected.  Is it possible that LabVIEW is excepting these events and not allowing then into the code.  The path as I see it is

dll -> WinAPI -> ActiveX -> LabVIEW

One thing this dll requires is a windows handle and I am wondering if LabVIEW itself is reads the events directly instead of ignoring them.  The reason I bring it up is that the tablet works like a mouse and I am wondering if it is absorbing these commands directly and not allowing them to be passed through the ActiveX object. Like this

dll-> WinAPI -> LabVIEW

therefore the event is never generated.  That is why I wish I could speak with someone at NI that could explain that process better, but it seems like there is no one at NI who knows any high level issues.

---

First this are not high level issues but lowest low level issues. Some of it certainly is more Windows related than LabVIEW so support from MS, as unlikely it is to get that, would be at its place. NI people are not there nor can't really help you debug your VB issues.

Second you say it is a tablet and works like a mouse, then I'm wondering if Windows is not simply claiming it as a Human Interface Device itself and not really letting you control it yourself in your VB control.

Rolf Kalbermatter