Re: IHTMLAttributeCollection, IHTMLDOMAttribute, and E_NOINTERFACE (Source Program)

From:

"Jeffrey Walton" <noloader@gmail.com>

Newsgroups:

microsoft.public.vc.atl

Date:

24 Dec 2006 20:15:38 -0800

Message-ID:

<1167020138.463470.254550@n51g2000cwc.googlegroups.com>

#include "StdAfx.h"

//
// Code basis was presented by Philip Patrick
// in 'Loading and parsing HTML using MSHTML'
//
// http://www.codeproject.com/internet/parse_html.asp
//

#define _WIN32_IE 0x0500 // IMarkupServices
#define _WIN32_DCOM // CoInitializeEx(...)

#pragma warning( disable: 4192 )
#pragma warning( disable: 4278 )
#import "mshtml.tlb" // MSHTML Namespace and Guids
#pragma warning( default: 4192 )
#pragma warning( default: 4278 )

#include <windows.h>
#include <atlbase.h> // CComPtr<>, CoInitializeEx, etc
#include <mshtml.h> // MSHTML Object and Interfaces
#include <assert.h>

// Standard C++ Library
#include <iostream>

HRESULT hr = S_OK;

int main(int argc, char* argv[])
{
 CComBSTR Page = OLESTR( "<HTML>" );
 Page += OLESTR( "<HEAD>" );
 Page += OLESTR( "<TITLE>Hello World Title</TITLE>" );
 Page += OLESTR( "</HEAD>" );
 Page += OLESTR( "<BODY>" );
 Page += OLESTR( "Center Paragraph 1" );
 Page += OLESTR( "Italic Paragraph 2" );
 Page += OLESTR( "<UL class=\"download\"><LI>List 1, Item 1</LI>" );
 Page += OLESTR( "<LI>List 1, Item 2</LI></UL>" );
 Page += OLESTR( "<UL><LI>List 2, Underline Item 1</LI>" );
 Page += OLESTR( "<LI>List 2, Item 2</LI></UL>" );
 Page += OLESTR( "</BODY>" );
 Page += OLESTR( "</HTML>" );

 try
 {
 // Get CComPtr< > in a try block so they can do their job
 CComPtr< MSHTML::IHTMLDocument2 > pDocument = NULL;
 CComPtr< IPersistStreamInit > pStream = NULL;
 CComPtr< MSHTML::IMarkupServices > pMarkupServices = NULL;
 CComPtr< MSHTML::IMarkupContainer > pContainer = NULL;
 CComPtr< MSHTML::IMarkupPointer > pBegin = NULL;
 CComPtr< MSHTML::IMarkupPointer > pEnd = NULL;
 CComPtr< MSHTML::IHTMLDocument2 > pNewDocument = NULL;
 CComPtr< MSHTML::IHTMLElementCollection > pCollection = NULL;

 ///////////////////////////////////////////////////////////////////
 hr = CoInitializeEx( NULL, COINIT_APARTMENTTHREADED );
 if( FAILED( hr ) ) { throw __LINE__; }

 ///////////////////////////////////////////////////////////////////
 // Create a Document to bootstrap the process
 CoCreateInstance(CLSID_HTMLDocument, NULL,
 CLSCTX_INPROC_SERVER, IID_IHTMLDocument2,
 reinterpret_cast<PVOID*>( &pDocument) );
 if( NULL == pDocument.p ) { throw __LINE__; }

 ///////////////////////////////////////////////////////////////////
 hr = pDocument->QueryInterface( IID_IPersistStreamInit,
 reinterpret_cast<PVOID*>( &pStream ) );
 if( FAILED( hr ) ) { throw __LINE__; }

 ///////////////////////////////////////////////////////////////////
 hr = pStream->InitNew();
 if( FAILED( hr ) ) { throw __LINE__; }

 ///////////////////////////////////////////////////////////////////
 hr = pDocument->QueryInterface( IID_IMarkupServices,
 reinterpret_cast<PVOID*>( &pMarkupServices ) ) ;
 if( FAILED( hr ) ) { throw __LINE__; }

 ///////////////////////////////////////////////////////////////////
 hr = pMarkupServices->CreateMarkupPointer( &pBegin );
 if( FAILED( hr ) ) { throw __LINE__; }

 ///////////////////////////////////////////////////////////////////
 hr = pMarkupServices->CreateMarkupPointer( &pEnd );
 if( FAILED( hr ) ) { throw __LINE__; }

 ///////////////////////////////////////////////////////////////////
 hr = pMarkupServices->ParseString( Page, 0, &pContainer, pBegin,
pEnd );
 if( FAILED( hr ) ) { throw __LINE__; }

 ///////////////////////////////////////////////////////////////////
 pContainer->QueryInterface( IID_IHTMLDocument,
 reinterpret_cast<PVOID*>( &pNewDocument ) );
 if( FAILED( hr ) ) { throw __LINE__; }

 ///////////////////////////////////////////////////////////////////
 hr = pNewDocument->get_all( &pCollection );
 if( FAILED( hr ) ) { throw __LINE__; }

 ///////////////////////////////////////////////////////////////////
 for( INT i = 0; i < pCollection->length; i++ )
 {
 CComVariant v;
 v.intVal = i;
 v.vt = VT_I4;

 CComPtr< IDispatch > pDispatch = NULL;
 pDispatch = pCollection->item( v );

 if( NULL != pDispatch.p )
 {
 CComPtr< MSHTML::IHTMLElement > pElement = NULL;
 CComPtr< MSHTML::IHTMLDOMNode > pDOMNode = NULL;

 hr = pDispatch->QueryInterface( IID_IHTMLElement,
(VOID**)&pElement );
 if( FAILED( hr ) ) { throw __LINE__; }

 std::wcout << (wchar_t*)pElement->tagName << L":" << std::endl;

 CComBSTR Text;
 hr = pElement->get_innerText( &Text );
 if( S_OK == hr && NULL != Text.m_str )
 {
 std::wcout << (wchar_t*)Text;
 }
 std::cout << std::endl << std::endl;

 hr = pDispatch->QueryInterface( IID_IHTMLDOMNode,
(VOID**)&pDOMNode );
 if( FAILED( hr ) ) { throw __LINE__; }

 CComPtr< IDispatch > pAttributes = NULL;
 hr = pDOMNode->get_attributes( &pAttributes );
 if( FAILED( hr ) ) { throw __LINE__; }

 CComPtr< IHTMLAttributeCollection > pAttributeCollection =
NULL;
 hr = pAttributes->QueryInterface( IID_IHTMLAttributeCollection,
 (PVOID*)&pAttributeCollection );
 if( FAILED( hr ) ) { throw __LINE__; }

 LONG length = 0;
 hr = pAttributeCollection->get_length( &length );
 if( FAILED( hr ) ) { length = 0; } // try to recover...
 // for( INT j = 0; j < pAttributeCollection->length; j++ )
 for( INT j = 0; j < length; j++ )
 {
 ///////////////////////////////////////////////////////////
 ///////////////////////////////////////////////////////////
 CComPtr< IHTMLDOMAttribute > pAttribute = NULL;
 hr = pAttributeCollection->QueryInterface(
 IID_IHTMLDOMAttribute, (PVOID*)&pAttribute);
 //if( FAILED( hr ) ) { throw __LINE__; }

 if( FAILED( hr ) ) { continue; }

 CComBSTR AttributeName( L"" );
 CComVariant AttributeValue;
 pAttribute->get_nodeName( &AttributeName );
 pAttribute->get_nodeValue( &AttributeValue );

 std::wcout << (wchar_t*)AttributeName << L"=";
 std::wcout << (wchar_t*)AttributeValue << std::endl;
 ///////////////////////////////////////////////////////////
 ///////////////////////////////////////////////////////////
 }
 }
 }
 }
 catch( UINT line )
 {
 std::wcout << std::endl;
 std::wcout << L"COM Error near Line " << line << std::endl;
 std::wcout << std::hex << L" 0x" <<hr;
 std::wcout << L" (Win32: " << std::dec << HRESULT_CODE( hr );
 std::wcout << L")" << std::endl;
 }

 CoUninitialize( );

 return HRESULT_CODE( hr );
}