How to set object class type for OLE automation

> When testing Dolphin for the development of an OLE automation client I
> ran into some trouble. I need to communicate with an OLE server (Act
> 2000) to access the database. The problem starts when I connect to a
> IDispatch interface through a property of my main application object.
> I think that I need to set the object type explicitly to allow certain
> overloaded functions to work.
>
> For example:
>
> "Connect to ACT and open database"
> db := ActOleIDatabase new.
> db open: 'c:\actdb\test.dbf'.
> db validateUser: 'Frank Sonnemans' sPassword: ''.
>
> db isOpen.
>
> "get contact IDispatch interface of type ActOleIContact"
> contacts := db contact.
> contacts moveFirst.
>
> "get first contacts name"
> contacts data: 26.
>
> ------------
> The result
>
> IDispatch(ExternalStructure)>>hresultError:
> IDispatch>>invokeId:flags:parms:retVal:
> IDispatch>>invokeId:flags:parms:
> IDispatch>>doesNotUnderstand:
> UndefinedObject>>{unbound}doIt
> CompiledExpression>>value:
> SmalltalkWorkspace>>evaluateRange:ifFail:debug:
> SmalltalkWorkspace>>evaluateRange:ifFail:
> SmalltalkWorkspace>>displayIt
> Symbol>>forwardTo:
>
> ------------
> If I look at the definition of the data: method of the ActOleIContact
> method I see:
> data: nField
> "Answer the <variant> value of the 'Data' property of the receiver."
>
> ^(self getPropertyId: 308 item: nField)
>
> Executing this manually for the contact object works:
> contacts getPropertyId: 308 item: 26.
>
> My conclusion is that the wrong method gets called because the system
> does not know the class type of the contacts object.
>
> So how do I tell the system which class the object belongs to?
>
> Regards,
>
>
> Frank

> Frank,
> "Frank Sonnemans" <[hidden email]> wrote in message
> news:[hidden email]...
> [...]
> > "get contact IDispatch interface of type ActOleIContact"
> > contacts := db contact.
> > contacts moveFirst.
> >
> > "get first contacts name"
> > contacts data: 26.
> [...]
>
> I'd guess that you're getting an IDispatch rather than an ActOleIContact.
> Display the result of evaluating
>
>     contacts class
>
> If it's IDispatch, try this:
>
>     contacts := db contact queryInterface: ActOleIContact.
>
> and then check the class again.  There are other ways to make sure you're
> getting the right class, but that's probably the simplest.
>
> Don