如何在VC环境下编写程序读取XML文件

如何在VC环境下编写程序读取XML文件?清提供源代码.谢谢.
#import <msxml3.dll> named_guids  //导入动态库，装了IE5就有
using namespace MSXML2;     //引用命名空间，一般可以把命名空间理解成类和接口的集合，呵呵，对不对我也不知道了
#include <vector>
using namespace std;
struct FIELD
{
public:
 CString  name;
 CString  type;
 CString  length;
 CString  explain;
 CString  allowNull;
 CString  autoIncrease;
};
class Xml
{
public:
 Xml(void);
 ~Xml(void);
private:
 HRESULT hr;
 MSXML2::IXMLDOMDocumentPtr pDoc; //XML文档接口指针
public:
 void AddKey(CString moduleName,CString keyName, CString keyValue);
 CString ReadKeyValue(CString moduleName, CString keyName);
private:
 void NewDocument(CString moduleName, CString keyName, CString keyValue);
public:
 bool ReadTable(CTreeCtrl * tree);
 bool ReadFields(CString tableName,vector<FIELD> &fields);
 bool SaveTable(vector<FIELD> fields,CString tableName,bool bNew);
};
//-------------------------------------------------------------------------------------------------------------------------------------
上面是头文件，这是cpp文件
#include "StdAfx.h"
#include "xml.h"
Xml::Xml(void)
{
 CoInitialize(NULL);                       //初始化COM
 hr=CoCreateInstance(MSXML2::CLSID_DOMDocument,NULL,CLSCTX_ALL,MSXML2::IID_IXMLDOMDocument,(void**)&pDoc); //创建XML文档实例
}
Xml::~Xml(void)
{
 CoUninitialize();
}
void Xml::AddKey(CString moduleName,CString keyName, CString keyValue)
{
 CString selectString="AppSetting/"+moduleName;                //XML节点定位字符串，定位到节点名为