Reg Event Callback

[Gatet]

I´m debugging a program allready finished, and I can´t get out what is this function doing and why. I have read the help file and also have a look to the examples, but it´s still not so clear.

Somebody knows what this function is doing and when the "On show message event callback" subVi is called? (see attachement)

Thanks

[Gatet]

Here is the block diagram of the auxiliar subVi. If somebody needs more information, please just ask.

[Gatet]

I would thank so much if somebody can give me some idea. This function is not working at the moment (or I suppose so) and I should solve it.

[Khalid]

It appears you are using an ActiveX control, and this ActiveX has callback events wherein on some specific task happening, it "calls back" LabVIEW to inform about it.  You get to know about these callbacks when you register for them.  That's what the Reg Event Callback is for. 

The VI to the left of the reg node is the callback VI, i.e., it gets called or run rather when you get the callback from the ActiveX Control.  To debug, you can start off by putting a message box in the callback VI.  This way a msg box will popup whenever you get the callback. And you can go from there. 

Hope this make sense. 

-Khalid

[falkpl]

A callback is a function which is called (when it is registered) when an activeX event happens.  The Vi is strictly typed and defined by the activeX event associated with it.  This is a nice feature if you plan to incorporate activeX controls in an event driven programming model.  An example is on double click for an activeX event .

Paul

[Gatet]

Ok, thanks a lot for both, it is giving a bit of light.

Yuju!