How do I access an ActiveX control's interface when have its generic control refnum in hand?

[smercurio_fc]

I don't know of a way to do that in LabVIEW, but perhaps someone else may know. If you were using .NET then you could use reflection to accomplish the task.

[Been bitten by LabVIEW]

There must be a way of getting the ActiveX refnum and cast it.  Will explore it a bit more.

[Adam_H]

Hey all,

This is an interesting discussion that we have going on here.  What kind of information is in your control?  I think that might help to track down how this might be done.

[Been bitten by LabVIEW]

Its quite irrelevant actually. I just want to be able to interrogate an OCX to find the appropriate interface.

Sorry, gotta go. Thanks

Adrian

[Been bitten by LabVIEW]

Well, I've looked at the flattened string of the refnums as retreived by the Controls[] and by passing a refnum of the AX control directly.  Looks like the actual refnum with type attached contains GUIDs where the one received from the VI's FP does not.  There is a common 0x4070 value as the second element that may indicate that the control is a ActiveX container, but other than that, I see no way of mapping. 😞  That sucks!

Attached is the information that I received.  Looks like I'm giving up. 😞

[Been bitten by LabVIEW]

In case anyone is interested, just tried a "to more specific class" without success.  It actually had less data when flattened. 😞

Message Edited by Been bitten by LabVIEW on 11-21-2008 11:21 AM

[smercurio_fc]

If you were able to get the dispatch GUID then you should be able to figure out the class of the ActiveX control based on the GUIDs in the registry. You won't be able to perform any casting because, as I indicated, I don't believe this operation is even possible, even outside of LabVIEW. I may be wrong on this last point, though - I just don't know.

[Been bitten by LabVIEW]

The GUIDs are only on the wire that is attached to the ActiveX refnum DIRECTLY.  Thus it contains the type information including the GUIDs.

I want to convert the control refnum that is pointing at the ActiveX container to give me the same type of connector.

Here is the block diagram.

Message Edited by Been bitten by LabVIEW on 11-21-2008 04:10 PM

[smercurio_fc]

As you've found out, when you get the reference via the Controls[] property all you get is a generic reference. Even if you cast it to be an ActiveXContainer all you get is a generic ActiveXContainer. You can cast it to a specific ActiveX control by wiring a (direct) reference to an ActiveX control, but you have no way of knowing if the cast is correct since the casting is likely to give no error.

I don't know if it's possible to do what you want with ActiveX controls. Perhaps Adam may be able to dig something up.

[Adam_H]

Hi All, I have been messing with it and keep running into the same problems everyone else is.  I have not given up hope yet.  I will keep everyone updated with anything I find.