4.6.13 Skeleton OLE Automation server

Putting all the previous elements together, the main program for an Automation server might look something like this:

define constant $my-class-id = make-GUID(...);

define method main-program () => ()

  if (OLE-util-register-only?()) // [un]register and terminate
    register-automation-server($my-class-id, 
                               "Foo.Bar",
                               "Simple OLE Automation server");

  else
    initialize-my-application(); // create window etc.

    // create and register the factory object:

    with-class-factory (clsid: $my-class-id,
                        class: <my-dispatch-object>,
                        typeinfo: make(<disp-type-info>, ...))

      // normal Windows event loop:

      with-stack-structure (pmsg :: <PMSG>)
        while(GetMessage(pmsg, $NULL-HWND, 0, 0))
          TranslateMessage(pmsg);
          DispatchMessage(pmsg);
        end while;
      end with-stack-structure;

    end with-class-factory;

    values()

  end if;

end method main-program;

However, if the program uses DUIM to implement its user interface, the event loop will be provided by DUIM, so the main program will look something like:

define method main-program () => ()
  if (OLE-util-register-only?()) // [un]register and terminate
    register-automation-server($my-class-id, "Foo.Bar",
      "a simple OLE Automation server example");
  else
    let frame = make(<my-frame>);
    with-class-factory (clsid: $my-class-id,
                        class: <my-dispatch-object>,
                        typeinfo: ...))
      start-frame(frame);
    end with-class-factory;
  end if;
end method main-program;

Some application programs can be used either interactively or by Automation control. In such a case, you might want to create a class factory only if the program was actually initiated by an Automation controller. For this purpose, you can do something like this:

...

let factory = #f;

if (OLE-util-automation?())
  factory := make(<class-factory>, ...);
end if;

... // body of program

revoke-registration(factory); // does nothing if argument is #f

...

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OLE, COM, ActiveX and DBMS Reference - 31 MAR 2000