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/*!

    \example activeqt/comapp

    \title COM App Example (ActiveQt)

    The COM App example shows how to use ActiveQt to develop a Qt

    application that can be automated via COM. Different QObject

    based classes are exposed as COM objects that communicate with the

    GUI of the running Qt application. The APIs of those COM objects

    has been designed to resemble the APIs of standard COM

    applications; i.e. those from Microsoft Office.

    \snippet examples/activeqt/comapp/main.cpp 2

    The first class \c Application represents the application object. It

    exposes read-only properties \c documents and \c id to get access to the

    list of documents, and an identifier. A read/write property \c visible

    controls whether the QTabWidget-based user interface of the application 

    should be visible, and a slot \c quit() terminates the application.

    The \e RegisterObject attribute is set to make sure that instances of this

    class are registered in COM's running object table (ROT) - this allows COM

    clients to connect to an already instantiated COM object.

    \snippet examples/activeqt/comapp/main.cpp 1

    The \c DocumentList class stores a list of documents. It provides an API

    to read the number of documents, to access each document by index and to 

    create a new document. The \c application property returns the root object.

    \snippet examples/activeqt/comapp/main.cpp 0

    The \c Document class finally represents a document in the application.

    Each document is represented by a page in the application's tab widget, and

    has a title that is readable and writable through the document's API.

    The \c application property again returns the root object.

    \snippet examples/activeqt/comapp/main.cpp 3

    The implementation of the \c Document class creates a new page for the tab

    widget, and uses the title of that page for the title property. The page 

    is deleted when the document is deleted.

    \snippet examples/activeqt/comapp/main.cpp 4

    The \c DocumentList implementation is straightforward.

    \snippet examples/activeqt/comapp/main.cpp 5

    The \c Application class initializes the user interface in the constructor,

    and shows and hides it in the implementation of \c setVisible(). The object

    name (accessible through the \c id property) is set to \c "From QAxFactory" 

    to indicate that this COM object has been created by COM. Note that there is 

    no destructor that would delete the QTabWidget - this is instead done in the 

    \c quit() slot, before calling QApplication::quit() through a single-shot-timer, 

    which is necessary ensure that the COM call to the slot is complete.

    \snippet examples/activeqt/comapp/main.cpp 6

    The classes are exported from the server using the QAxFactory macros. Only

    \c Application objects can be instantiated from outside - the other APIs can

    only be used after accessing the respective objects throught the \c Application

    API.

    \snippet examples/activeqt/comapp/main.cpp 7

    The main() entry point function creates a QApplication, and just enters the

    event loop if the application has been started by COM. If the application

    has been started by the user, then the \c Application object is created and 

    the object name is set to "From Application". Then the COM server is started,

    and the application object is registered with COM. It is now accessible to

    COM clients through the client-specific APIs.

    Application exiting is controlled explicitly - if COM started the application, 

    then the client code has to call quit(); if the user started the application,

    then the application terminates when the last window has been closed.

    Finally, the user interface is made visible, and the event loop is started.

    A simple Visual Basic application could now access this Qt application. In VB,

    start a new "Standard Exe" project and add a project reference to the comappLib

    type library. Create a form with a listbox "DocumentList", a static label 

    "DocumentsCount" and a command button "NewDocument". Finally, implement the code 

    for the form like this:

    \snippet doc/src/snippets/code/doc_src_examples_activeqt_comapp.qdoc 0

    To build the example you must first build the QAxServer library.

    Then run \c qmake and your make tool in

    \c{examples\activeqt\comapp}.

*/