External code to act on a LabVIEW ActiveX event

[PeterB]

Hi folks,

Are there any examples showing how to write a LabVIEW executable which can act as an ActiveX Automation Server and support event callbacks from other languages ? e.g. within say a C# or .NET program, I want to do the reverse of what you see in the LabVIEW example here:

C:\Program Files\National Instruments\LabVIEW 8.6\examples\comm\axevent.llb\ActiveX Event Callback for Excel.vi

I would like an external client's callback code (accessing my LabVIEW ActiveX automation server) to be executed when I programmatically initiate the event from my LabVIEW code

regards

Peter

[PeterB]

OK, so rewording my situation and question.

I have a LabVIEW program with ActiveX Server enabled. Properties and methods can be accessed fine from other programming languages. (specifically a C scripting language used by Test Complete).

How do I fire an ActiveX event from the LabVIEW side which subsequently will cause some callback code to run in the other language.

Essentially I want to do the reverse of what you see in the LabVIEW example here:

C:\Program Files\National Instruments\LabVIEW 8.6\examples\comm\axevent.llb\ActiveX Event Callback for Excel.vi

So instead of the NewWorkbook event coming from Excel causing "NewWorkbookCallback.vi" to run , I will be (programatically) firing my_own_custom_event from my vi causing some code to run in the other language.

regards

Peter Badcock

Product Development

ResMed Ltd

[PeterB]

Perhaps what I am trying to do is not possible.

If one opens up the example I referred to at [2] , Right Click on the Automation refnum constant and "Select ActiveX Class" "Browse" and navigate to the type library file (*.tlb) created by the LabVIEW Application Builder (for a particular EXE you create - mine is named HelloWorld), you will find it only contains properties and methods - it does NOT contain events.

Is that a limitation of LabVIEW ? Can LabVIEW not export events into type libraries ? (at least that is what is suggested in the help file [1]).

I don't want to register for events from other applications, I want to register for events from a LabVIEW application (albeit eventually from another programming environment). I cannot seem to build a LabVIEW application which exports events into its type library.

regards

Peter Badcock

Product Development

ResMed Ltd

[1]

Enable ActiveX server

—(Windows)

Enables the ActiveX server

so the application can respond to requests from ActiveX clients. The functionality of the ActiveX server in the application is a subset of the LabVIEW ActiveX server. When you build an application myapp.exe, Application Builder also creates an ActiveX type library myapp.tlb. The type library defines an application class and a virtual instrument class and exports both Application

properties

and

methods

and VI

properties

and

methods

. When you distribute the application, include the type library with the executable file.

[2] C:\Program Files\National Instruments\LabVIEW 8.6\examples\comm\axevent.llb\ActiveX Event Callback for Excel.vi

[mje]

I've wondered this several times over the years as well and not come up with a solution. Recently I was hoping to find a way to do this in a .NET context, but came up dry.

*waits...*