> However, the basic problem is still that passing an IUnknown to a method
> expecting a variant seems to fail. The call goes through allright, but
> casting
> the variant back to an IUnknown returns an unnassigned interface.
>> What happens if you put a break point on the assignment in the collection
item? Is the variant NIL?
It should not be, else all I could say is that the problem lies elsewhere.
> Does casting an interface to a variant increment the reference count? that
> could
> be the problem?
>> It could be a problem, but the interface would still NOT be NIL. Have not
looked at the compiled code to see what happens.
Myles.
> Myles Penlington <[EMAIL PROTECTED]> on 07/08/2000 12:25:35
>
> Please respond to [EMAIL PROTECTED]
>
> To: Multiple recipients of list delphi <[EMAIL PROTECTED]>
> cc: (bcc: Phillip Middlemiss/NZ Forest Research Institute/NZ)
>
> Subject: RE: [DUG]: Aaarrgh! Variants@#%^$3!!
>
>
>
> Don't quite see why you are using variants in this case, but it should not
> make any difference.
>
> MyList.add(aNewObject as IUnknown)
>
> This is the line you need to check. Does AnewObject support the IUnknown
> interface?
> It would appear from your comments that it does not.
>
> I would probably use Interface variables rather than Variants by
> preference.
> The only reason to use OLEVariants would be if you are going to pass the
> object reference to VBScript/JScript eg ASP/OleAutomation.
>
> eg MyList.Add( AInterface: IUnknown);
>
> "My stubs are descended from TInterfacedObject but implement stub methods
> for
> IDispatch. "
>
> Why do this?? Seems a complete waste of time. Does not achieve anything.
> Your comment previous to this does however make complete sense, but it
> does
> not require this to be done.
>
> Myles.
>
>
> > -----Original Message-----
> > From: [EMAIL PROTECTED]
> > [SMTP:[EMAIL PROTECTED]]
> > Sent: Monday, August 07, 2000 11:58 AM
> > To: Multiple recipients of list delphi
> > Subject: [DUG]: Aaarrgh! Variants@#%^$3!!
> >
> >
> >
> > Hi all,
> >
> > I am writing a client GUI that is talking to a number of Java servers
> via
> > J-Integra (therefore COM) although that is really only background and
> not
> > vital
> > to the problem.
> >
> > I have written stubs for all the classes that I need from the servers so
> I
> > can
> > build the GUI without the servers needing to be up to date or even
> > running.My
> > stubs are descended from TInterfacedObject but implement stub methods
> for
> > IDispatch.
> >
> > The problem boils down to storing the stub objects in a list that deals
> > with
> > OLEVariants. The List uses a TCollectionItem internally, storing each
> > added
> > variant inside a TCollectionItem descendant that holds onto an
> OLEVariant.
> > Adding a new item to the list looks like this:
> >
> > MyList.add(aNewObject as IUnknown)
> >
> > which automatically casts the IUnknown to an OLEVariant which the Add
> > method is
> > expecting. The Add method assigns the OLEVariant to a newly created
> > CollectionItem descendant.
> >
> > However! Inside the add method, before I do anything, in the
> > Evaluate/Modify
> > dialog, I cast the passed OLEVariant back to an IUnknown and it informs
> me
> > that
> > it is nil!!!!
> >
> > Is this because the IDispatch interface is stubbed so therefore not a
> real
> > ActiveX object? or am I just missing something with variants? This is my
> > first
> > time using them.
> >
> > Any help would be great,
> >
> > cheers,
> >
> > Phil Middlemiss.
> >
> >
> >
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> > Website: http://www.delphi.org.nz
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> Website: http://www.delphi.org.nz
>
>
>
>
>
>
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> Website: http://www.delphi.org.nz
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