MFC读取XML文件并解析

现在经常会对XML文件进行操作，怎么在MFC下去读和解析XML文件呢？直接上代码：

首先得等在stdafx.h中加入这句，以引入MSXML命名空间

#import <msxml3.dll> named_guids
using namespace MSXML2;

然后再要使用的类的头文件加入：  

//XML Parser intellectural pointer (used in parsing XML file)

MSXML2::IXMLDOMDocument2Ptr   m_plDomDocument;
MSXML2::IXMLDOMElementPtr   m_pDocRoot;

然后在初始化函数中加入对XML COM的初始化：

//intianlize XML Parser COM 
::CoInitialize(NULL);
HRESULT hr = m_plDomDocument.CreateInstance(MSXML2::CLSID_DOMDocument);
    
if(FAILED(hr))
{
    _com_error er(hr);
    AfxMessageBox(er.ErrorMessage());
    EndDialog(1);
}

接着是具体的函数：

void CDemoDlg::OnBnClickedButtonOpenxml()
{
    // at first ,we should clear m_strXML's contents to show new data
    m_strXMLData = "";

    CFileDialog fileDlg(TRUE);
    if(IDOK == fileDlg.DoModal())
    {
        m_strXMLPath = fileDlg.GetPathName();
        m_strXMLContents = "Empty document";

        //just in case you don't get anything
        UpdateData(FALSE);

        //Specify XML file name
        CString strFileName = m_strXMLPath;

        //Convert XML file name string to something COM can handle
        _bstr_t bstrFileName;
        bstrFileName = strFileName.AllocSysString();

        //Call the IXMLDOMDocumentPtr's load function to load XML file
        variant_t vResult;
        vResult = m_plDomDocument->load(bstrFileName);

        if(((bool)vResult) == TRUE ) //success
        {
            //Convert bstr to something you can use in VC++
            _bstr_t bstrDocContents = m_plDomDocument->xml;
            m_strXMLContents = (LPCTSTR) bstrDocContents;

            //get XML data and show on Edit Control
            MSXML2::IXMLDOMNodePtr m_pXMLRoot = m_plDomDocument->documentElement;  //first child is point
            //m_strXMLData = _T(",") + DisplayXMLChildren(m_pXMLRoot);
            
            //loop to show get point's Lon and Lan and save in map<CString,CString>LonLanPoints
            for(MSXML2::IXMLDOMNodePtr pChild = m_pXMLRoot->firstChild; pChild != NULL; pChild = pChild->nextSibling)
            {
                DisplayXMLChildren(pChild); 
            }
        }
        else
        {
            m_strXMLContents = "Document FAILED to load!";
        }

        UpdateData(FALSE);
    }
}


//in case of overload data we use before, we should add one button for clear the data(Ready to transfrom)
CString CDemoDlg::DisplayXMLChildren(MSXML2::IXMLDOMNodePtr pParent)
{
    //Display current node's name
    //every parent's node name is POINT
    CString strElement = ((LPCTSTR)pParent->nodeName);  //output is point

    //loop to get data  pChild's parent node is point,and point's parent node is road
    for(MSXML2::IXMLDOMNodePtr pChild = pParent->firstChild; pChild != NULL; pChild = pChild->nextSibling)
    {
        //strElement += ((LPCTSTR)pChild->nodeName);  
        CString nodeName = ((LPCTSTR)pChild->nodeName);        
        CString Lon = _T("Lon");
        CString Lan = _T("Lan");
        CString currentLon,currentLan;

        if ( nodeName == Lon )
        {
            currentLon = ((LPCTSTR)pChild->text);
        }        
        if ( nodeName == Lan )
        {
            currentLan = ((LPCTSTR)pChild->text);
        }

        //add one point's Lon and Lan to map
        LonLanPoints.insert(currentLon,currentLan);
    }
    return strElement;
}

XML结构为：
<road>
<point>
    <id><id/>
    <Lon></Lon>
    <Lat></Lat>
</road>