Com Wrapper Question

Using the Active/X component wizard, I wrapped a set of COM objects provided
by Quiksoft that access and manage POP3 mailboxes.  One of the properties is
supposed to return a collection of Messages after they are downloaded from
the server.

The main POP3 object, in my case EMIPOP3Main, generated a #message method,
which represent the property that holds a collection of message objects
downloaded from the server.  According to the documentation, this is
supposed to return the collection object EMIPOP3Messages, which is also
wrapped.  However, when I execute the EMIPOP3Main>>#messages method, I get
an instance of IDispatch, and none of the EMIPOP3Messages work (it tries to
do something via the IDispatch>>#doesNotUnderstand: protocol, and generates
and error).

It may be I'm expecting too much from the COM wrapper generator, but I
though I would get an instance of EMIPOP3Messages from
EMIPOP3Main>>#messages .

The generated code for EMIPOP3Main>>#messages is:

messages
"Answer the <variant> value of the 'Messages' property of the receiver.
Helpstring: 'property Messages'"
    | answer |
    answer := VARIANT new.
    self
        get_Messages: answer.
    ^answer asObject

Any help appreciated - thanks -

jlo

Some further information -

Even though an instance of IDispatch is returned, the
IDispatch>>#doesNotUnderstand: logic allows the #count method to be sent,
and it returns the value I expect (1).

However, it does not allow the #item: method to be sent.  The
IDispatch>>#doesNotUnderstand: does find the dispatch id of #item: (0), but
when it executes the method on IDispatch>>#invokeId:flags:parms:retVal:, it
gets error number: -2147352573, which translates to message "Member not
Found".

I'm passing the parameter 1 to it.  I tried passing the parater 0 to it, as
sometimes the COM collections are zero based, but I got the same result.

Any insights welcome - TIA -

jlo

Jeffrey Odell wrote:


Jeff,

I wonder if the EMIPOP3Messages is supposed to be an enumerator
interface to a collection of messages. Since you're getting an IDispatch
back (presumably pointing to some valid COM object), you might try
modifying the messages method to do something like:

...
^answer asObject queryInterface: EMIPOP3Messages.

I can't help but wonder if you have hold of the correct COM object, but
just need to get the right interface on it. You might be able to send
that item: message.

Just a thought,

Eric


> Any help appreciated - thanks -
>
> jlo
>
>
>

Yes!  That was it.  The wrapper caused the parameter to be set up slightly
differently.  I had to do the same thing on the #item: method of the
EMIPOP3Messages to turn the result into the individual message object,
EMIPOP3Message in my case.

Thanks for the pointer - I was looking for methods on the superclass of
IDispatch to set up the generated wrappers around the IDispatch but didn't
find it there.

Blair/Andy - if you think the generator should have taken care of this, I
can provide the examples you need.  In the mean time, Eric has provided a
work-around to get me moving.

Thanks again, Eric -

jlo

"Eric Winger" <[hidden email]> wrote in message
news:[hidden email]...
>
>
> Jeffrey Odell wrote:
>
> > Using the Active/X component wizard, I wrapped a set of COM objects
provided
> > by Quiksoft that access and manage POP3 mailboxes.  One of the
properties is
> > supposed to return a collection of Messages after they are downloaded
from
> > the server.
> >
> > The main POP3 object, in my case EMIPOP3Main, generated a #message
method,
> > which represent the property that holds a collection of message objects
> > downloaded from the server.  According to the documentation, this is
> > supposed to return the collection object EMIPOP3Messages, which is also
> > wrapped.  However, when I execute the EMIPOP3Main>>#messages method, I
get
> > an instance of IDispatch, and none of the EMIPOP3Messages work (it tries
to
> > do something via the IDispatch>>#doesNotUnderstand: protocol, and
generates