Step 7: Deriving the application class from TOcModule

ObjectComponents requires that the class you derive from TApplication must also inherit from TOcModule.

In addition, the application object needs to implement a CreateOleObject method with the following signature:

TUnknown* CreateOleObject(uint32 options, TRegList* link);

The purpose of the function is to create a server document for linking or embedding. The server must create a client window and return a pointer of type TOcRemView*. Here is how OWLOCF2 declares this procedure:

class TScribbleApp : public TApplication,
public TOcModule {
 public:
  TScribbleApp();
  TUnknown* CreateOleObject(uint32 options, TRegLink* link);

and here is how it implements the procedure:

TUnknown*
TScribbleApp::CreateOleObject(uint32 options, TRegLink* link)
{
 if (!link) // factory creating an application only, no view required
  link = &scribbleLink;    // need to have a view for this app
 TOleFrame* olefr = TYPESAFE_DOWNCAST(GetMainWindow(), TOleFrame);
 CHECK(olefr);
 FileData.FileName[0] = 0;
 TScribbleWindow* client = new TScribbleWindow(
   olefr->GetRemViewBucket(), FileData, link);
 client->Create();
 return client->GetOcRemView();
}

ObjectWindows uses the CreateOleObject method to inform your application when OLE needs the server to create an object. The TRegLink* parameter indicates which object to create.