How to sink HTML document events for WebBrowser host

// Declare these as members of your IWebBrowser2 sink.
CComObject<CDocumentSink> *pSink;
CComPtr<IUnknown> pSrcUnk;
DWORD dwDocCookie;

STDMETHODIMP CWebOCWindow::DocumentComplete(IDispatch *wbDisp, VARIANT* url) {
	HRESULT hr;
	CComPtr<IDispatch> pDocDisp;
	CComQIPtr<IHTMLDocument2> pDoc;
	CComPtr<IUnknown> wbDispUnk;

	// Sink only the topmost document. Slightly more complex logic will be needed
	// if you wish to sink multiple pages embedded in a frameset.
	hr = wbDisp->QueryInterface(IID_IUnknown, reinterpret_cast<void **>(&wbDispUnk));
	if (FAILED(hr)) {
		goto cleanup;
	}
	if (wbDispUnk == browserUnk) {
		hr = CComObject<CDocumentSink>::CreateInstance(&pSink);
		if (FAILED(hr)) {
			goto cleanup;
		}
		// Get the current document from the WebBrowser.
		// If you'll be surfing to sites with frames, and want to avoid sinking all but
		// the top-level document - i.e., the frameset - make sure to sink only when the
		// IUnknown obtained from wbDisp and the original IUnknown of the hosted 
		// WebBrowser control are equal.
		hr = webOC->get_Document(&pDocDisp);
		if (FAILED(hr)) {
			goto cleanup;
		}
		hr = pDocDisp->QueryInterface(&pSrcUnk);
		if (FAILED(hr)) {
			goto cleanup;
		}
		// If this is not an HTML document (e.g., it's a Word doc or a PDF), don't sink. 
		pDoc = pDocDisp;
		if (!pDoc) {
			goto cleanup;
		}

		hr = AtlAdvise(pSrcUnk, pSink, DIID_HTMLDocumentEvents, &dwDocCookie);
		if (FAILED(hr)) {
			goto cleanup;
		}
	}

cleanup:
	// Only smart pointers used - nothing to do here.
	return hr;
}
				

void OnClick(VARIANT_BOOL *bProcessEvent) {
        AtlTrace("CDocumentSink:OnClick - Obtained a click on the document\n");
	*bProcessEvent = TRUE;
}

STDMETHODIMP Invoke(DISPID dispidMember, REFIID riid, LCID lcid, WORD wFlags, DISPPARAMS *pdispparams, VARIANT *pvarResult,
			  EXCEPINFO *pexcepinfo, UINT *puArgErr) {
        HRESULT hr;

	if (dispidMember == DISPID_CLICK) {
	    VARIANT_BOOL bEventRet;
	    OnClick(&bEventRet);
	    pvarResult->vt = VT_BOOL;
	    pvarResult->boolVal = bEventRet;
            hr = S_OK;
	} else {
            hr = DISP_E_MEMBERNOTFOUND;
	}
	return hr;
}
				

STDMETHODIMP CWebOCWindow::BeforeNavigate2(IDispatch *pDisp, VARIANT *url, VARIANT *Flags, VARIANT *TargetFrameName,
							 VARIANT *PostData, VARIANT *Headers, VARIANT_BOOL *Cancel) {
	if (pSrcUnk) {
		hr = AtlUnadvise(pSrcUnk, DIID_HTMLDocumentEvents, dwDocCookie);
		pSrcUnk.Detach();
	}
	return S_OK;
}
				

Dim WithEvents doc As HTMLDocument

Private Sub Form_Load()
    WebBrowser1.Navigate "http://www.microsoft.com/"
End Sub

Private Sub WebBrowser1_DocumentComplete(ByVal pDisp As Object, URL As Variant)
    Dim htm As IHTMLDocument2
    
    On Error Resume Next
    Set htm = WebBrowser1.Document
    If Err.Number = 0 Then
        MsgBox "HREF is " & htm.location.href
    End If
    
    Set doc = htm
End Sub

Private Function doc_onclick() As Boolean
    MsgBox "Clicked the document!"
    ' Tell IE to continue processing the event.
    doc_onclick = True
End Function

Private Sub WebBrowser1_BeforeNavigate2(ByVal pDisp As Object, URL As Variant, Flags As Variant, _
						    TargetFrameName As Variant, PostData As Variant, Headers As Variant, _
						    Cancel As Boolean)
    set doc = Nothing
End Sub