Can event listener be registered with ActiveX control on (e.g.) an Excel worksheet

I can register Excel server, workbook, and worksheet events and the callbacks get called. However, if I have an ActiveX control on a worksheet, I cannot register an event for it - even though I can see which events are available - and have the callback called when they fire (if they are firing). Below shows a series of steps to register and react to a worksheet event and then my attempt to register an event with the OLE control. Any ideas? (Note I have closed up the MATLAB output as much as possible to save space.)

>> x=actxserver('Excel.Application')  
>> x.Visible=1  
>> hb=x.Workbooks.Open('c:\myfolder\mybook.xlsm')  
>> hs=hb.ActiveSheet  
>> hs.events

     ... some events
     Deactivate = void Deactivate()  
     ... and several more

>> hs.registerevent({'Deactivate', @eventcallback})  
>> hs.eventlisteners

     ans = 'Deactivate'    @eventcallback  
     'Excel event occurred'  % Message from event handler, eventcallback.m

>> hs.OLEObjects.Item(1).Object.Caption  
   ans = My pushbutton  % Caption on my ActiveX pushbutton control

>> hs.OLEObjects.Item(1).Object.events

  ... some events  
  Click = void Click()  
   ... and several more

>> hs.OLEObjects.Item(1).Object.registerevent({'Click', @eventcallback})  
>> hs.OLEObjects.Item(1).Object.eventlisteners  

ans =   
     {}  % Does not register listener callback much less call it (also no complaints from MATLAB, Excel, etc)

[Guillaume]

People with enough reputation can edit all posts. If you look at your profile, you'll see the reputation required to earn each type of privilege.

The only thing I did is edit the formatting of your post to make it more readable (removed blank lines between lines of code).

[Walter Roberson]

I think I edited it to reformat it before Guillaume did.

Answer 1

[Guillaume]

It looks like you need to acquire the interface of the activex control explicitly in order to register events. In other words, this does not work:

hs.OLEObjects.Item(1).Object.registerevent({'Click', @eventcallback})

but this appears to:

o =  hs.OLEObjects.Item(1).Object;
registerevent(o, {'Click', @eventcallback}); %or o.registerevent(...)

No idea why, matlab sometimes exhibits some very odd behaviour with regards to COM.

[Dave Watson]

Isn't THAT interesting. Of course, it's exactly what I did - without noticing the difference - to register the workbook, worksheet, etc events, which worked. Also, o.eventlisteners lists them but hs.OLEObjects.Item(1).Object.eventlisteners returns {}. Strange. Anyway, thanks a lot - that's great!!