/***********  The header file ******************************/
class CXMLConfig 
{
private:
	IXMLDOMDocument* m_pXMLDocument;
	CString m_strFileName;
public:
	CXMLConfig(void);
	~CXMLConfig(void);
	CXMLConfig(CString strConfigFileName);
	HRESULT LoadXMLDocument();
	CString GetValue(CString strXPath);
	void SetFileName(CString strFileName);
};

/***********  The implementation file ******************************/

#include "stdafx.h"
#include ".\xmlconfig.h"
CXMLConfig::CXMLConfig(void)
{
	CoInitialize(NULL);
	m_pXMLDocument = NULL;
	m_strFileName = "";
}
CXMLConfig::~CXMLConfig(void)
{
	if (m_pXMLDocument!=NULL) {
		m_pXMLDocument->Release();
		m_pXMLDocument = NULL;
	}
	CoUninitialize();
}
CXMLConfig::CXMLConfig(CString strConfigFileName)
{
	m_strFileName = strConfigFileName;
}
void CXMLConfig::SetFileName(CString strFileName)
{
	m_strFileName = strFileName;
}
BOOL CXMLConfig::LoadXMLDocument(BOOL bValidateOnParse , BOOL bResolveExternals )
{
	HRESULT hRes ;
	BOOL bRet = FALSE;
	CFileFind ff;
	if (!ff.FindFile(m_strFileName)) {
		CString strMsg;
		strMsg.Format("The file '%d' is not found",m_strFileName);
		AfxMessageBox(strMsg);
		return bRet;
	}
   	hRes = CoCreateInstance(CLSID_DOMDocument, NULL, CLSCTX_INPROC_SERVER,IID_IXMLDOMDocument, (void**)&m_pXMLDocument);
	if ( hRes == S_OK ) {
		COleVariant var(m_strFileName) ;
		VARIANT_BOOL bResult;
		hRes = m_pXMLDocument->load(var,&bResult) ;
		if ( hRes == S_OK && bResult == VARIANT_TRUE ) {
			//	Success
			bRet = TRUE;
		}
		else {
			AfxMessageBox("file can not be loaded");
		}
	}
	return bRet ;
}
/********************************************************************************
Function		:	GetValue
Parameters		:
	strXPath	:	xPath to query from the xml file
*********************************************************************************/
CString CXMLConfig::GetValue(CString strXPath)
{
	CString strValue = "";
	CComPtr<IXMLDOMElement> pRoot;
	CComPtr<IXMLDOMNode> pXMLDOMNodeResult;
	CComPtr<IXMLDOMElement> pElement;
	CComPtr<IXMLDOMText> pText;
	CComPtr<IXMLDOMNode> pXMLDOMNode;
	BSTR bStrXPath;
	m_pXMLDocument->get_documentElement(&pRoot);
	if ( pRoot == NULL ) {
		return strValue;
	}
	bStrXPath = strXPath.AllocSysString() ;
	pRoot->selectSingleNode(bStrXPath,&pXMLDOMNodeResult);
	::SysFreeString(bStrXPath) ;
	if ( pXMLDOMNodeResult == NULL ) {
		return strValue;
	}
	pXMLDOMNodeResult->QueryInterface(IID_IXMLDOMElement,(void**)&pElement);
	if ( pElement == NULL ) {
		return strValue;
	}
	pElement->get_firstChild(&pXMLDOMNode);
	if ( pXMLDOMNode == NULL ) {
		return strValue;
	}
	pXMLDOMNode->QueryInterface(IID_IXMLDOMText,(void**)&pText);
	if ( pText == NULL ) {
		return strValue;
	}
	BSTR bStrTextContent ;
	pText->get_text(&bStrTextContent) ;
	strValue = CString(bStrTextContent) ;
	return strValue;
}