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TQAxBase Class Reference
[TQAxContainer module]

The TQAxBase class is an abstract class that provides an API to initalize and access a COM object. More...

This class is part of the TQt ActiveTQt Extension.

#include <qaxbase.h>

Inherited by TQAxObject and TQAxWidget.

List of all member functions.

Public Members

Signals

Properties

Protected Members

Detailed Description

This class is defined in the TQt ActiveTQt Extension, which can be found in the qt/extensions directory. It is not included in the main TQt API.

The TQAxBase class is an abstract class that provides an API to initalize and access a COM object.

TQAxBase is an abstract class that cannot be used directly, and is instantiated through the subclasses TQAxObject and TQAxWidget. This class provides the API to access the COM object directly through its IUnknown implementation. If the COM object implements the IDispatch interface, the properties and methods of that object become available as TQt properties and slots. 

    connect( buttonBack, TQ_SIGNAL(clicked()), webBrowser, TQ_SLOT(GoBack()) );

Properties exposed by the object's IDispatch implementation can be read and written through the property system provided by the TQt Object Model (both subclasses are TQObjects, so you can use setProperty() and property() as with TQObject). Properties with multiple parameters are not supported. 

    activeX->setProperty( "text", "some text" );
    int value = activeX->property( "value" );

Write-functions for properties and other methods exposed by the object's IDispatch implementation can be called directly using dynamicCall(), or indirectly as slots connected to a signal. 

    webBrowser->dynamicCall( "GoHome()" );

Outgoing events supported by the COM object are emitted as standard TQt signals. 

    connect( webBrowser, TQ_SIGNAL(TitleChanged(const TQString&)),
             this, TQ_SLOT(setCaption(const TQString&)) );

TQAxBase transparently converts between COM data types and the equivalent TQt data types. Some COM types have no equivalent TQt data structure.

Supported COM datatypes are listed in the first column of following table. The second column is the TQt type that can be used with the TQObject property functions. The third column is the TQt type that is used in the prototype of generated signals and slots for in-parameters, and the last column is the TQt type that is used in the prototype of signals and slots for out-parameters.

COM type TQt property in-parameter out-parameter
VARIANT_BOOL bool bool bool&
BSTR TQString const TQString& TQString&
char, short, int, long int int int&
uchar, ushort, uint, ulong uint uint uint&
float, double double double double&
DATE TQDateTime const TQDateTime& TQDateTime&
CY TQ_LLONG TQ_LLONG TQ_LLONG&
OLE_COLOR TQColor const TQColor& TQColor&
SAFEARRAY(VARIANT) TQValueList<TQVariant> const TQValueList<TQVariant>& TQValueList<TQVariant>&
SAFEARRAY(BYTE) TQByteArray const TQByteArray& TQByteArray&
SAFEARRAY(BSTR) TQStringList const TQStringList& TQStringList&
VARIANT type-dependent const TQVariant& TQVariant&
IFontDisp* TQFont const TQFont& TQFont&
IPictureDisp* TQPixmap const TQPixmap& TQPixmap&
IDispatch* TQAxObject* (read-only) TQAxBase::asVariant() TQAxObject* (return value)
IUnknown* TQAxObject* (read-only) TQAxBase::asVariant() TQAxObject* (return value)
SCODE, DECIMAL unsupported unsupported unsupported

Supported are also enumerations, and typedefs to supported types.

To call the methods of a COM interface described by the following IDL 

    dispinterface IControl
    {
    properties:
        [id(1)] BSTR text;
        [id(2)] IFontDisp *font;

    methods:
        [id(6)] void showColumn( [in] int i );
        [id(3)] bool addColumn( [in] BSTR t );
        [id(4)] int fillList( [in, out] SAFEARRAY(VARIANT) *list );
        [id(5)] IDispatch *item( [in] int i );
    };
use the TQAxBase API like this: 
    TQAxObject object( "<CLSID>" );

    TQString text = object.property( "text" ).toString();
    object.setProperty( "font", TQFont( "Times New Roman", 12 ) );

    connect( this, TQ_SIGNAL(clicked(int)), &object, TQ_SLOT(showColumn(int)) );
    bool ok = object.dynamicCall( "addColumn(const TQString&)", "Column 1" ).toBool();

    TQValueList<TQVariant> varlist;
    TQValueList<TQVariant> parameters;
    parameters << TQVariant( varlist );
    int n = object.dynamicCall( "fillList(TQValueList<TQVariant>&)", parameters ).toInt();

    TQAxObject *item = object.querySubItem( "item(int)", 5 );

Note that the TQValueList the object should fill has to be provided as an element in the parameter list of TQVariants.

If you need to access properties or pass parameters of unsupported datatypes you must access the COM object directly through its IDispatch implementation or other interfaces. Those interfaces can be retrieved through queryInterface(). 

    IUnknown *iface = 0;
    activeX->queryInterface( IID_IUnknown, (void**)&iface );
    if ( iface ) {
        // use the interface
        iface->Release();
    }

To get the definition of the COM interfaces you will have to use the header files provided with the component you want to use. Some compilers can also import type libraries using the #import compiler directive. See the component documentation to find out which type libraries you have to import, and how to use them.

If you need to react to events that pass parameters of unsupported datatypes you can use the generic signal that delivers the event data as provided by the COM event.

Member Type Documentation

TQAxBase::PropertyBag

A TQMap that can store properties as name:value pairs.

Member Function Documentation

TQAxBase::TQAxBase ( IUnknown * iface = 0 )

Creates a TQAxBase object that wraps the COM object iface. If iface is 0 (the default), use setControl() to instantiate a COM object.

TQAxBase::~TQAxBase () [virtual]

Shuts down the COM object and destroys the TQAxBase object.

See also clear().

TQVariant TQAxBase::asVariant () const

Returns a TQVariant that wraps the COM object. The variant can then be used as a parameter in e.g. dynamicCall().

void TQAxBase::clear () [virtual]

Disconnects and destroys the COM object.

If you reimplement this function you must also reimplement the destructor to call clear(), and call this implementation at the end of your clear() function.

TQString TQAxBase::control () const

Returns the name of the COM object wrapped by this TQAxBase object. See the "control" property for details.

void TQAxBase::disableClassInfo ()

Disables the class info generation for this ActiveX container. If you don't require any class information about the ActiveX control use this function to speed up the meta object generation.

Note that this function must be called immediately after construction of the object (without passing an object identifier), and before calling TQAxWidget->setControl().

void TQAxBase::disableEventSink ()

Disables the event sink implementation for this ActiveX container. If you don't intend to listen to the ActiveX control's events use this function to speed up the meta object generation.

Some ActiveX controls might be unstable when connected to an event sink. To get OLE events you must use standard COM methods to register your own event sink. Use queryInterface() to get access to the raw COM object.

Note that this function should be called immediately after construction of the object (without passing an object identifier), and before calling TQAxWidget->setControl().

void TQAxBase::disableMetaObject ()

Disables the meta object generation for this ActiveX container. This also disables the event sink and class info generation. If you don't intend to use the TQt meta object implementation call this function to speed up the meta object generation.

Some ActiveX controls might be unstable when used with OLE automation. Use standard COM methods to use those controls through the COM interfaces provided by queryInterface().

Note that this function must be called immediately after construction of the object (without passing an object identifier), and before calling TQAxWidget->setControl().

TQVariant TQAxBase::dynamicCall ( const TQCString & function, const TQVariant & var1 = TQVariant ( ), const TQVariant & var2 = TQVariant ( ), const TQVariant & var3 = TQVariant ( ), const TQVariant & var4 = TQVariant ( ), const TQVariant & var5 = TQVariant ( ), const TQVariant & var6 = TQVariant ( ), const TQVariant & var7 = TQVariant ( ), const TQVariant & var8 = TQVariant ( ) )

Calls the COM object's method function, passing the parameters var1, var1, var2, var3, var4, var5, var6, var7 and var8, and returns the value returned by the method, or an invalid TQVariant if the method does not return a value or when the function call failed.

If function is a method of the object the string must be provided as the full prototype, for example as it would be written in a TQObject::connect() call. 

    activeX->dynamicCall( "Navigate(const TQString&)", "www.trolltech.com" );

Alternatively a function can be called passing the parameters embedded in the string, e.g. above function can also be invoked using 

    activeX->dynamicCall("Navigate(\"www.trolltech.com\");
All parameters are passed as strings; it depends on the control whether they are interpreted correctly, and is slower than using the prototype with correctly typed parameters.

If function is a property the string has to be the name of the property. The property setter is called when var1 is a valid TQVariant, otherwise the getter is called. 

    activeX->dynamicCall( "Value", 5 );
    TQString text = activeX->dynamicCall( "Text" ).toString();
Note that it is faster to get and set properties using TQObject::property() and TQObject::setProperty().

It is only possible to call functions through dynamicCall() that have parameters or return values of datatypes supported by TQVariant. See the TQAxBase class documentation for a list of supported and unsupported datatypes. If you want to call functions that have unsupported datatypes in the parameter list, use queryInterface() to retrieve the appropriate COM interface, and use the function directly. 

    IWebBrowser2 *webBrowser = 0;
    activeX->queryInterface( IID_IWebBrowser2, (void**)&webBrowser );
    if ( webBrowser ) {
        webBrowser->Navigate2( pvarURL );
        webBrowser->Release();
    }

This is also more efficient.

Example: qutlook/centralwidget.cpp.

TQVariant TQAxBase::dynamicCall ( const TQCString & function, TQValueList<TQVariant> & vars )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Calls the COM object's method function, passing the parameters in vars, and returns the value returned by the method. If the method does not return a value or when the function call failed this function returns an invalid TQVariant object.

The TQVariant objects in vars are updated when the method has out-parameters.

void TQAxBase::exception ( int code, const TQString & source, const TQString & desc, const TQString & help ) [signal]

This signal is emitted when the COM object throws an exception while called using the OLE automation interface IDispatch. code, source, desc and help provide information about the exception as provided by the COM server and can be used to provide useful feedback to the end user. help includes the help file, and the help context ID in brackets, e.g. "filename [id]".

TQString TQAxBase::generateDocumentation ()

Returns a rich text string with documentation for the wrapped COM object. Dump the string to an HTML-file, or use it in e.g. a TQTextBrowser widget.

bool TQAxBase::initialize ( IUnknown ** ptr ) [virtual protected]

This virtual function is called by setControl() and creates the requested COM object. ptr is set to the object's IUnknown implementation. The function returns TRUE if the object initialization succeeded; otherwise the function returns FALSE.

The default implementation interprets the string returned by control(), and calls initializeRemote(), initializeLicensed() or initializeActive() if the string matches the respective patterns. If no pattern is matched, or if remote or licensed initialization fails, CoCreateInstance is used directly to create the object.

See the control property documentation for details about supported patterns.

The interface returned in ptr must be referenced exactly once when this function returns. The interface provided by e.g. CoCreateInstance is already referenced, and there is no need to reference it again.

bool TQAxBase::initializeActive ( IUnknown ** ptr ) [protected]

Returns an active instance running on the current machine, and returns the IUnknown interface to the running object in ptr. This function returns TRUE if successful, otherwise returns FALSE.

This function is called by initialize() if the control string contains the substring "}&".

See also initialize().

bool TQAxBase::initializeLicensed ( IUnknown ** ptr ) [protected]

Creates an instance of a licensed control, and returns the IUnknown interface to the object in ptr. This functions returns TRUE if successful, otherwise returns FALSE.

This function is called by initialize() if the control string contains the substring "}:". The license key needs to follow this substring.

See also initialize().

bool TQAxBase::initializeRemote ( IUnknown ** ptr ) [protected]

Creates the instance on a remote server, and returns the IUnknown interface to the object in ptr. This function returns TRUE if successful, otherwise returns FALSE.

This function is called by initialize() if the control string contains the substring "/{". The information about the remote machine needs to be provided in front of the substring.

See also initialize().

bool TQAxBase::isNull () const

Returns TRUE if there is no COM object loaded by this wrapper; otherwise return FALSE.

See also control.

PropertyBag TQAxBase::propertyBag () const

Returns a name:value map of all the properties exposed by the COM object.

This is more efficient than getting multiple properties individually if the COM object supports property bags.

Warning: It is not guaranteed that the property bag implementation of the COM object returns all properties, or that the properties returned are the same as those available through the IDispatch interface.

void TQAxBase::propertyChanged ( const TQString & name ) [signal]

If the COM object supports property notification, this signal gets emitted when the property called name is changed.

bool TQAxBase::propertyWritable ( const char * prop ) const [virtual]

Returns TRUE if the property prop is writable; otherwise returns FALSE. By default, all properties are writable.

Warning: Depending on the control implementation this setting might be ignored for some properties.

See also setPropertyWritable() and propertyChanged().

long TQAxBase::queryInterface ( const TQUuid & uuid, void ** iface ) const

Requests the interface uuid from the COM object and sets the value of iface to the provided interface, or to 0 if the requested interface could not be provided.

Returns the result of the QueryInterface implementation of the COM object.

See also control.

TQAxObject * TQAxBase::querySubObject ( const TQCString & name, const TQVariant & var1 = TQVariant ( ), const TQVariant & var2 = TQVariant ( ), const TQVariant & var3 = TQVariant ( ), const TQVariant & var4 = TQVariant ( ), const TQVariant & var5 = TQVariant ( ), const TQVariant & var6 = TQVariant ( ), const TQVariant & var7 = TQVariant ( ), const TQVariant & var8 = TQVariant ( ) )

Returns a pointer to a TQAxObject wrapping the COM object provided by the method or property name, passing passing the parameters var1, var1, var2, var3, var4, var5, var6, var7 and var8.

If name is provided by a method the string must include the full function prototype.

If name is a property the string must be the name of the property, and var1, ... var8 are ignored.

The returned TQAxObject is a child of this object (which is either of type TQAxObject or TQAxWidget), and is deleted when this object is deleted. It is however safe to delete the returned object yourself, and you should do so when you iterate over lists of subobjects.

COM enabled applications usually have an object model publishing certain elements of the application as dispatch interfaces. Use this method to navigate the hierarchy of the object model, e.g. 

    TQAxWidget outlook( "Outlook.Application" );
    TQAxObject *session = outlook.querySubObject( "Session" );
    if ( session ) {
        TQAxObject *defFolder = session->querySubObject(
                                "GetDefaultFolder(OlDefaultFolders)",
                                "olFolderContacts" );
        //...
    }

Example: qutlook/centralwidget.cpp.

bool TQAxBase::setControl ( const TQString & )

Sets the name of the COM object wrapped by this TQAxBase object. See the "control" property for details.

void TQAxBase::setPropertyBag ( const PropertyBag & bag )

Sets the properties of the COM object to the corresponding values in bag.

Warning: You should only set property bags that have been returned by the propertyBag function, as it cannot be guaranteed that the property bag implementation of the COM object supports the same properties that are available through the IDispatch interface.

See also propertyBag().

void TQAxBase::setPropertyWritable ( const char * prop, bool ok ) [virtual]

Sets the property prop to writable if ok is TRUE, otherwise sets prop to be read-only. By default, all properties are writable.

Warning: Depending on the control implementation this setting might be ignored for some properties.

See also propertyWritable() and propertyChanged().

void TQAxBase::signal ( const TQString & name, int argc, void * argv ) [signal]

This generic signal gets emitted when the COM object issues the event name. argc is the number of parameters provided by the event (DISPPARAMS.cArgs), and argv is the pointer to the parameter values (DISPPARAMS.rgvarg). Note that the order of parameter values is turned around, ie. the last element of the array is the first parameter in the function. 

    void Receiver::slot( const TQString &name, int argc, void *argv )
    {
        VARIANTARG *params = (VARIANTARG*)argv;
        if ( name.startsWith( "BeforeNavigate2(" ) ) {
            IDispatch *pDisp = params[argc-1].pdispVal;
            VARIANTARG URL = *params[argc-2].pvarVal;
            VARIANTARG Flags = *params[argc-3].pvarVal;
            VARIANTARG TargetFrameName = *params[argc-4].pvarVal;
            VARIANTARG PostData = *params[argc-5].pvarVal;
            VARIANTARG Headers = *params[argc-6].pvarVal;
            bool *Cancel = params[argc-7].pboolVal;
        }
    }

Use this signal if the event has parameters of unsupported data types. Otherwise, connect directly to the signal name.

Property Documentation

TQString control

This property holds the name of the COM object wrapped by this TQAxBase object.

Setting this property initilializes the COM object. Any COM object previously set is shut down.

The most efficient way to set this property is by using the registered component's UUID, e.g. 

    ctrl->setControl( "{8E27C92B-1264-101C-8A2F-040224009C02}" );
The second fastest way is to use the registered control's class name (with or without version number), e.g. 
    ctrl->setControl( "MSCal.Calendar" );
The slowest, but easiest way to use is to use the control's full name, e.g. 
    ctrl->setControl( "Calendar Control 9.0" );

If the component's UUID is used the following patterns can be used to initialize the control on a remote machine, to initialize a licensed control or to connect to a running object:

The first two patterns can be combined, e.g. to initialize a licensed control on a remote machine: 
    ctrl->setControl("DOMAIN/user:password@server/{8E27C92B-1264-101C-8A2F-040224009C02}:LicenseKey");

The control's read function always returns the control's UUID, if provided including the license key, and the name of the server, but not including the username, the domain or the password.

Set this property's value with setControl() and get this property's value with control().

This file is part of the TQt toolkit. Copyright © 1995-2007 Trolltech. All Rights Reserved.

Copyright © 2007 TrolltechTrademarks
TQt 3.3.8