Retrieve javascript array object with C++ using DISPID_NEWENUM fails on IE9

Question

following a similar question i answered some time ago, i found out that when trying to enumerate the object, using IDispatch::Invoke(DISPID_NEWENUM,...) fails with DISP_E_EXCEPTION on IE9.
This happens with IDispatch and IDispatchEx, on any javascript array.

needless to say that the code works great on IE6-IE8, and fails only on IE9.

The same question also appears in the MSDN dev forums with no luck so far.

Here's a code snippet to demonstrate what I tried to do. notice that pDispatch is the javascript's array variant.

// invoke the object to retrieve the enumerator containing object
CComVariant varResult;

DISPPARAMS dispparamsNoArgs = {0};
EXCEPINFO excepInfo = {0};
UINT uiArgErr = (UINT)-1;  // initialize to invalid arg
HRESULT hr = pDispatch->Invoke(DISPID_NEWENUM, IID_NULL, LOCALE_USER_DEFAULT, DISPATCH_METHOD | DISPATCH_PROPERTYGET, &dispparamsNoArgs, &varResult, &excepInfo, &uiArgErr);

// if failed - retry with IDispatchEX
if (FAILED(hr))
{
   CComPtr<IDispatchEx> pDispatchEx;
   pDispatchEx = pDispatch; // Implied query interface

   hr = pDispatchEx->InvokeEx(DISPID_NEWENUM, LOCALE_USER_DEFAULT, DISPATCH_METHOD | DISPATCH_PROPERTYGET, &dispparamsNoArgs, &varResult, &excepInfo, NULL);

   if (FAILED(hr))
      return false;
}

Does anyone have any idea why this code always fails (IDispatch and IDispatchEx) with HRESULT of DISP_E_EXCEPTION specifically on IE9?

Thanks.

Answer 1

IEnumVARIANT may work. Although when I tried it IEnumVARIANT::Next always was returning E_FAIL, the element was fetched correctly. Didn't have time or need to get to the bottom of this.

It worked for me, but if it didn't I was intended to use IDispatchEx: when enumerated members of array objects passed by IE they all had "0", "1" etc.., not "length" method though, must be in it's typeinfo, haven't checked. I think you get the idea.

Sorry can't post pseudo code this site won't allow me without following some special formatting rules

hth