> I've tried to figure this out on my own but I'm stumped.

> I've written a inproc server with ATL and attempted to implement a
> collection object.

> Here is the IDL (this is a snippet, there are other interface/coclass defs):

> [
>   object,
>   uuid(FE933A1D-8DE0-4098-8D27-49D64BFA2622),
>   dual,
>   helpstring("ITGLStrings Interface"),
>   pointer_default(unique),
>   oleautomation
>  ]
>  interface ITGLStrings : IDispatch
>  {
>   [propget, id(0), helpstring("method Item")] HRESULT Item([in, out]
> VARIANT* index, [out, retval] VARIANT* pItem);
>   [propget, id(1), helpstring("property Count")] HRESULT Count([out, retval]
> long *pVal);
>   [id(2), helpstring("method Add")] HRESULT Add([in] BSTR pName, [in] BSTR
> pData, [in] BSTR pMediaFilename, [out, retval] ITGLString** pString );
>   [id(3), helpstring("method Remove")] HRESULT Remove([in, out] VARIANT*
> index);
>   [propget, id(DISPID_NEWENUM), helpstring("property _NewEnum"), restricted]
> HRESULT _NewEnum([out, retval] IUnknown** pVal);
>  };

> The weird part is this:

> When I test the component in Visual Basic, if I using the TGLString.Item
> property this way:

> TGLStrings.Item("somekey")

> It works fine.  If I pass an numeric value to the Item property:

> TGLStrings.Item(1)

> I get a "Runtime Error 5, Invalid Procedure Call or Argument."  Now here is
> the kicker - when I compile the VB test project to an executable and run it,
> TGLStrings.Item(1) works!  It only doesn't work in when running the code
> under the VB IDE.

> If I create the component in VB and use VB's Collection class, it works
> fine.  I even tried copying the TGLStrings IDL interface definition,
> produced by VB, into the my ATL project but with no luck.

> What am I missing?

> Thank you in advance,

> Joel

> Well I made a discovery:
> -------------------------

> If I do this:

> TGLStrings.Add "some name"
> TGLStrings.Item 1
> TGLStrings.Remove 1

> Everything works fine.

> If I do this:

> TGLStrings.Add "some name"
> For Each Item In TGLStrings
>     ' do something
> Next

> TGLStrings.Item 1
> ' or
> TGLStrings.Remove 1

> The Item and Remove methods generate errors.

> The strange part is that if I pass a string to those methods:

> TGLStrings.Item "some name"
> TGLStrings.Remove "some name"

> It works!

> It also works if I compiled the VB tester into an EXE.  Go figure.

> What I'm wondering is if there is an issue in my get__NewEnum method...
> Since Item and Remove only fail in the VB IDE *after* the call to For Each
> ... In ... (which calls _NewEnum.)  This is going to drive me nuts...

> So any other ideas?

> Thanks for the help.

> BTW Here is my get_NewEnum code (I know it isn't efficient...)

> STDMETHODIMP CTGLStrings::get__NewEnum(IUnknown** pVal)
> {
>     int size = collection_.GetSize();
>     VARIANT* pVar = new VARIANT[size];

>    for(int idx = 0; idx < size; ++idx)
>   {
>       pVar[idx].vt       = VT_DISPATCH;
>       pVar[idx].pdispVal = collection_.GetValueAt(idx);
>   }

>   typedef CComObject<CComEnum<IEnumVARIANT,

&IID_IEnumVARIANT,
>                                                           VARIANT,
>                                                           _Copy<VARIANT> >

> enumVar;

>   enumVar* pEnumVar = new enumVar;
>   pEnumVar->Init(&pVar[0], &pVar[size], NULL, AtlFlagCopy);

>   delete pVar;

>   return pEnumVar->QueryInterface(IID_IUnknown, (void**)pVal);
> }

> Check your code handling the Item index VARIANT. Perhaps you reject some
> valid vartype? (VT_I2 vs VT_I4 comes to mind...)

> --
> =====================================
> Alexander Nickolov
> Microsoft MVP [VC], MCSD

> MVP VC FAQ: http://www.mvps.org/vcfaq
> =====================================

> > Hey guys.
> <snip>

> OK.  It appears that the bug has to do with the data parameter being passed
> to the Item and Remove methods.
> Get this, if I don't call For Each ... In on the object when the Item/Remove
> methods are called, the VARIANT parameter, index.lVal is equal to 1.  If I
> call For Each ... In on the object before calling Item/Remove when one of
> those methods are called the value of index.lVal is equal to 1835009.  What
> is strange is that this parameter is an incoming parameter.  Doesn't the
> client allocate the memory for this parameter?  So how is it being
> corrupted?

> As I said, everything works when I compile the VB test program.  The error
> only occurs after calling For Each ... In before Item/Remove and *only*
> while in the VB IDE/debug mode.  Argh.

> Any ideas?