QAxWidget get pointer to my activeX control

Tony123

Hi guys simple question ..maybe :)

How can I achieve this in Qt:

// in MFC VC++ project
CWnd *pdfControl = GetDlgItem( IDC_PDFCREACTIVEX1 );
 ASSERT( pdfControl );
 LPUNKNOWN lpUnknown = pdfControl->GetControlUnknown();
 ASSERT( lpUnknown );

I find this

ui.myAxWidget.control()

but its return only QString I need LPUNKOWN

It's really important for me to get pointer to my ActiveX control somehow.

Thanks in advance

hskoglund

Hi, #include "windows.h" and #include "QUuid" and try

LPUNKNOWN lpUnknown;
ui.myAxWidget.queryInterface(QUuid(IID_IUnknown),(LPVOID*) &lpUnknown);

Then, to check to really got the correct LPUNKNOWN for your ActiveX control, you can try something like this: (it parties on the LPUNKNOWN above to retrieve some documentation for that ActiveX control)

LPDISPATCH pDispatch;
lpUnknown->QueryInterface(IID_IDispatch, (LPVOID*) &pDispatch);

LPTYPEINFO pTypeInfo;
pDispatch->GetTypeInfo(0,LOCALE_SYSTEM_DEFAULT,&pTypeInfo);

LPTYPELIB pTypeLib;
UINT uTypeInfoIndex;
pTypeInfo->GetContainingTypeLib(&pTypeLib,&uTypeInfoIndex);

BSTR bstrName,bstrDocString;
pTypeLib->GetDocumentation(-1,&bstrName,&bstrDocString,NULL,NULL);
QString sName((QChar*)bstrName,::SysStringLen(bstrName));
QString sDocString((QChar*)bstrDocString,::SysStringLen(bstrDocString));

// show what we've got
qDebug() << sName << sDocString;

Tony123

Thanks @hskoglund for reply.
When I type it like this:

	LPUNKNOWN lpUnknown;
	long lo = ui.axWidget->queryInterface(QUuid(ui.axWidget->control()), (LPVOID*)&lpUnknown);

lpUknown is null.

Thanks in advance!

hskoglund

Well that's because ->queryInterface() expects an Interface-flavored UUID, for example IID_IUnknown or IID_IDispatch etc. These are stored in the registry in the HKEY_CLASSES_ROOT\Interface part. You can use either IID_IUnknown as in my example above, or use its string representation like this:
long lo = ui.axWidget->queryInterface(QUuid("{00000000-0000-0000-c000-000000000046}"), (LPVOID*)&lpUnknown);

But using a CLSID-flavored UUID, like in your ...ui.axWidget->control())... example above, will fail and return the HRESULT 0x80004002 (No such interface supported)

Yeah, so there are many types of different UUIDs used in COM, you can read more here