IID_IHTMLElement Failing

Abhi Lahare

Hi, I am trying to get IID_IHTMLElement but its failing, in few cases. The GetlastError function returns 0 for these cases. I am using following function call to achive this, IHTMLElement * pElement = NULL; IHTMLDocument2 * pHTMLDoc = NULL; HRESULT hr; IServiceProvider * pSP = NULL; hr = pAccWindow->QueryInterface(IID_IServiceProvider, (void **)&pSP); hr = pSP->QueryService(IID_IHTMLElement, IID_IHTMLElement, (void **)&pElement); I do not get any exception, bur I getting pElement as NULL. I got these failure when I press the Browser BACK button in MSIE 6.0. Any pointer will be helpful, Thanks in Advance ARLahare

led mike

Abhi Lahare wrote:

The GetlastError function returns 0 for these cases.

You need to diagnose the HRESULT

led mike

Mark Salsbery

Without knowing anything about this, I did a quick SDK search. This sample code (and similar code found on Google) seems to be common -

// from "About Active Accessibility Support" in the PSDK

HRESULT hr;
IHTMLWindow2 * pWindow;
IHTMLElement * pElement;
hr = pSP->QueryService(IID_IHTMLWindow2, IID_IHTMLWindow2,
(void **)&pWindow);
if (FAILED(hr))
hr = pSP->QueryService(IID_IHTMLElement, IID_IHTMLElement,
(void **)&pElement);

// Release the Service Provider interface pointer.
pSP->Release();

if (SUCCEEDED(hr))
{
// Either a window or an element pointer was returned.
assert( pWindow || pElement);
....
code here...
// Release the pointers.
if (pElement)
pElement->Release();
if (pWindow)
pWindow->Release();
}

Maybe that helps? Mark

"Posting a VB.NET question in the C++ forum will end in tears." Chris Maunder

Stephen Hewitt

From my experience the IHTMLElement interface is not accessed via IServiceProvider but simply via QueryInterface on the element in question. GetLastError is not used for error handling in COM: COM is designed with remote access in mind and the GetLastError mechanism is thread specific. In your code what is pAccWindow?

Steve

Abhi Lahare

Thanks Stephen, I have seen code samples where IServiceProvider is used to accesses IHTMLElement and its working in my code for other cases. pAccWindow is the IAccessible pointer. Thanks for your help ARLahare

Abhi Lahare

Return value is E_INVALIDARG but not sure what is wrong with input parameter. Regards ARLahare

Mark Salsbery

According to the docs, the object "can be an element or a window". Have you tried querying for IID_IHTMLWindow2 first as documented? Mark

"Posting a VB.NET question in the C++ forum will end in tears." Chris Maunder

Abhi Lahare

yes