The QAxServer Module

To make an ActiveX control available to the COM system it must be registered in the system registry using five unique identifiers. These identifiers are provided by tools like guidgen or uuidgen. The registration information allows COM to localize the binary providing a requested ActiveX control, marshall remote procedure calls to the control and read type information about the methods and properties exposed by the control.

To create the ActiveX control when the client asks for it the server must export an implementation of a QAxFactory. Use the default factory when the server provides only a single ActiveX control, and implement a subclass of QAxFactory to provide multiple ActiveX controls. The default factory is available through a macro that takes the identifiers COM requires to locate the ActiveX control on the target system:

    QAXFACTORY_DEFAULT ( MyActiveX,
                "{ad90301a-849e-4e8b-9a91-0a6dc5f6461f}",
                "{87a5b65e-7fa9-4dc6-a176-47295988dcbd}",
                "{a6130ae9-8327-47ec-815b-d0b45a0d6e5e}",
                "{26c4e136-4e23-4347-af37-faf933b027e9}",
                "{a8f21901-7ff7-4f6a-b939-789620c03d83}" )
    

The QAxFactory class documentation explains how to use this macro, and how to implement and use custom factories.

For out-of-process executable servers, implement a main() function, instantiate a QApplication object, and enter the event loop just like any normal Qt application. By default the application will start as a standard Qt application, but if you pass -activex on the command line it will start as an ActiveX server. Use QAxFactory::isServer() to create and run a standard application interface, or to prevent a stand-alone execution:

    #include <qapplication.h>
    #include <qaxfactory.h>

    int main( int argc, char **argv )
    {
        QApplication app( argc, argv );
        if ( !QAxFactory::isServer() ) {
            // create and show main window...
        }
        return app.exec();
    }
    

    int main( int , char ** )
    {
        return 0;
    }
    

To build the ActiveX server executable run qmake to generate the makefile, and use your compiler's make tool as for any other Qt application. The make process will also register the controls in the system registry by calling the resulting executable with the -regserver command line option. See the Typical build errors list for information on problems that can occur when building the ActiveQt server executable.

If the ActiveX server is an executable, the following command line options are supported:

In-process servers can be registered using the regsvr32 tool available on all Windows systems.

Using the Controls

    <object ID="MyActiveX1" CLASSID="CLSID:ad90301a-849e-4e8b-9a91-0a6dc5f6461f">
       ...
    <\object>
    

    <object ID=...>
        <param name="name" value="value">
    <\object>
    

    class AxImpl : public QAxAggregated, public ISomeCOMInterface
    {
    public:
        AxImpl() {}

        long queryInterface( const QUuid &iid, void **iface )
        {
            *iface = 0;     
            if ( iid == IID_ISomeCOMInterface )
                *iface = (ISomeCOMInterface*)this;
            else
                return E_NOINTERFACE;

            AddRef();
            return S_OK;
        }
        
        // IUnknown
        QAXAGG_IUNKNOWN

        // ISomeCOMInterface
        ...
    }
    

    long AxImpl::queryInterface( const QUuid &iid, void **iface )
    {
        *iface = 0;
        if ( iid == IID_ISomeCOMInterface )
            *iface = (ISomeCOMInterface*)this;
        else
            return E_NOINTERFACE;

        AddRef();
        return S_OK;
    }
    

    HRESULT AxImpl::QueryInterface( REFIID iid, void **iface )
    {
        return controllingUnknown()->QueryInterface( iid, iface );
    }
    

    class MyActiveX : public QWidget,                       
                      public QAxBindable
    {
    	Q_OBJECT
    public:
        MyActiveX( QWidget *parent, const char *name = 0 );

        QAxAggregated *createAggregate()
        {
            return new AxImpl();
        }
        
    };
    

    QString MyFactory::exposeToSuperClass( const QString &key ) const
    {
        if ( key == "SmallActiveX" )
            return key;
        return QAxFactory::exposeToSuperClass( key );
    }