How to correctly call on onsubmit event using IWebBrowser2 interfaces (using c++)

I'm trying to call the onsubmit programmatically without clicking in the form button.

First i try to simply call the submit function of the IHTMLFormElement interface but the form does not correctly processed the input data:

CComPtr<IHTMLFormElement> ppvForm;
ppvForm->submit();

I read in the documentation and it says that the submit function do not call the onsubmit event, then i try to call the onsubmit event by using the IDispatch invoke method provided by the get_onsubmit of the IHTMLFormElement interface:

CComPtr<IHTMLFormElement> ppvForm;
...
_variant_t vResult;
_variant_t tvar;
hResult = ppvForm->get_onsubmit(&tvar); // <<< i get a NULL VARIANT here 

DISPPARAMS params = {0};
hResult = tvar.pdispVal->Invoke(
    DISPID_VALUE, 
    IID_NULL,
    LOCALE_SYSTEM_DEFAULT, 
    DISPATCH_METHOD, 
    &params, 
    &vResult, 
    NULL, 
    NULL);
if( SUCCEEDED(hResult) )
...

But the ppvForm->get_onsubmit call return S_OK with a NULL variant... (don't know why?!)

And in the end tried the fireEvent fro开发者_运维百科m the IHTMLDocument4 interface:

HRESULT hrRes=S_FALSE;
CComPtr<IHTMLDocument4> piDoc;
...
VARIANT_BOOL varRet;
CComPtr<IHTMLEventObj>pEvent;
hrRes=piDoc->createEventObject(NULL, &pEvent);

_variant_t vtEvent(pEvent);
hrRes=piDoc->fireEvent(_bstr_t(_T("onsubmit")), &vtEvent, &varRet);

The fireEvent now returns always E_INVALIDARG! don't know why? don't know if i need to put something in the vtEvent or the "onsubmit" string is invalid, don't know.

Can anyone point me in the right direction or tell me what I'm doing wrong?

---

If get_onsubmit() is returning S_OK and a NULL handler, then there is simply no onsubmit event handler assigned to the form to begin with.