what is different between dispinterface and interface in IDL ?

vohan   Posts: n/a

what is different between dispinterface and interface in IDL ? what is different between dispinterface and interface (with IDispatch) in IDL ? And how to implement dispinterface methods and props in VC++ (prefer ClassWizard) ? Any help will be appreciated.

vohan

#2   03-27-2001, 10:07 AM

Ed   Posts: n/a

Re: what is different between dispinterface and interface in IDL ? "vohan" <vohan2@vol.vnn.vn> wrote: > >what is different between dispinterface and interface (with IDispatch) in >IDL ? And how to implement dispinterface methods and props in VC++ (prefer >ClassWizard) ? >Any help will be appreciated. Reference material: Professional ATL COM Programming by Dr. Richard Grimes at WROX Press. Dispinterface indicates that the component supports IDispatch. You can access the methods for a dispinterface using IDispatch::Invoke(). Dispinterfaces don't have to return an HRESULT because IDispatch::Invoke() will. So they can have other return types in the definintion. VC++ has several methods for member access: _com_dispatch_propget() _com_dispatch_propput() _com_dispatch_method() _com_dispatch_raw_propget() _com_dispatch_raw_propput() _com_dispatch_raw_method() The prop methods use parameters indicating type of property. I would suggest going over Chapters 1 and 3 in the Wrox book. Selecting 'Support Connection Points' in the object Wizard will add a dispinterface to the IDL for outgoing interface.

Ed

#3   03-27-2001, 01:41 PM

Andy Friedman   Posts: n/a

Re: what is different between dispinterface and interface in IDL ? In addition, a dispinterface is not part of the object's vtable. This is inconsequential to scripting clients, but lowers performance considerably for VC++ clients. The general rule of thumb is don't use dispinterfaces except for events. Andy "Ed" <emedina@enovasoftware.com> wrote: > >"vohan" <vohan2@vol.vnn.vn> wrote: >> >>what is different between dispinterface and interface (with IDispatch) in >>IDL ? And how to implement dispinterface methods and props in VC++ (prefer >>ClassWizard) ? >>Any help will be appreciated. >Reference material: Professional ATL COM Programming by Dr. Richard Grimes >at WROX Press. > >Dispinterface indicates that the component supports IDispatch. You can access >the methods for a dispinterface using IDispatch::Invoke(). Dispinterfaces >don't have to return an HRESULT because IDispatch::Invoke() will. So they >can have other return types in the definintion. > >VC++ has several methods for member access: >_com_dispatch_propget() >_com_dispatch_propput() >_com_dispatch_method() >_com_dispatch_raw_propget() >_com_dispatch_raw_propput() >_com_dispatch_raw_method() >The prop methods use parameters indicating type of property. > >I would suggest going over Chapters 1 and 3 in the Wrox book. > >Selecting 'Support Connection Points' in the object Wizard will add a dispinterface >to the IDL for outgoing interface.