QAxBase: Error calling IDispatch member inAgentIP: Unknown error

[Kycho]

I do not understand why the error is happening.
The QAxWidget class works fine,
The QAxObject class does not work.

#define AGENT_ID "{74091A7F-FD8C-4440-96A2-CB2EB8BAD896}"
    QAxWidget *testWidget = new QAxWidget(AGENT_ID);
    testWidget->setProperty("inAgentIP","127.0.0.1"); // Good Word!
    qDebug() << testWidget->property("inAgentIP"); // output : 127.0.0.1

#define AGENT_ID "{74091A7F-FD8C-4440-96A2-CB2EB8BAD896}"
    QAxObject *testObj = new QAxObject(AGENT_ID);
    testObj->setProperty("inAgentIP","127.0.0.1"); // QAxBase: Error calling IDispatch member inAgentIP: Unknown error
    qDebug() << testObj->property("inAgentIP"); // output : null

QAxWidget should use QAxObject because it is difficult to move threads.
Thank you for your help.

[hskoglund]

Hi, just guessing, but if the COM object you're starting (AGENT_ID) requires a window (HWND), for example if it's an OCX or ActiveX control DLL, then that could explain why QAxWidget works as a container for it but QAxObject does not. (Because QAxObject does not create a window for the COM control.)

[Kycho]

@hskoglund

Thank you for your reply.

AGENT_ID is the CLSID of ocx (ActiveX).

https://doc.qt.io/qt-5/activeqt-container.html
I saw the page above.
In other words, does all ocx (ActiveX) mean to use QAxWidget?

[hskoglund]

Hi, yes. If the ActiveX control has a user interface (a window) then QAxWidget is needed as a container for that window.