首先建立一个XML文件，我的机器软件configuration如下：

Windows xp professional sp2

IE 6.0( 无关紧要)

VS 2003

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#import <msxml3.dll> //I have no idea why msxl4 cannot be used

                         //in my PC, may be something on personal

                         //discrimination

using namespace MSXML2;///the same to above///

-----------------------------------------------------------------------------------创建文件 

int CreateXMLFile(char * xml_file_name)

{   // create an xml file named xml_file_name comtemporily

 // if the return val is "0",it means that creation

 // if failed

 ::CoInitialize(NULL);// this item must be included

                            //it is fatal ,else it will failed

                            //then at last “::CoUninitialize();”

//matched

 MSXML2::IXMLDOMDocumentPtr pDoc;

 HRESULT hr = pDoc.CreateInstance(__uuidof(DOMDocument30));//         

//<msxml3.dll> version is 3.0

 if(!(SUCCEEDED(hr)))//faild

 {           

         return 0;

 }

 MSXML2::IXMLDOMElementPtr pPolicy=pDoc->createElement("Local"); 

 pDoc->appendChild(pPolicy); 

 { // the brackets including 1,2,3 can show the

    //tree structure of the xml file

    // nodes

       //1

         MSXML2::IXMLDOMElementPtr pPolicyType; 

         pPolicyType=pDoc->createElement("North");

         pPolicyType->Puttext("Piking");

         pPolicy->appendChild(pPolicyType);

         pPolicyType=pDoc->createElement("South");            

         pPolicy->appendChild(pPolicyType);

         {//2.1

                MSXML2::IXMLDOMElementPtr pControlType;

                pControlType=pDoc->createElement("Shanghai");     

                pControlType->Puttext("Xujiahui");

                pPolicyType->appendChild(pControlType);

                pControlType.Release();

         }//end 2.1

         pPolicyType=pDoc->createElement("East");

         pPolicy->appendChild(pPolicyType);   

         {//2.2

                MSXML2::IXMLDOMElementPtr pProcessType;

                pProcessType=pDoc->createElement("Heilongjiang");

                pProcessType->Puttext("harbin,Qiqihar");

                pPolicyType->appendChild(pProcessType);

                pProcessType=pDoc->createElement("Liaoning");     

                pProcessType->Puttext("ShenYang,Dalian");

                pPolicyType->appendChild(pProcessType);

                pProcessType.Release();

         }//end 2.2

         _variant_t varXml(xml_file_name);

         pDoc->save(varXml);    //save the file        

         pPolicy.Release();

         pPolicyType.Release();

 }//end 1

 pDoc.Release();

 ::CoUninitialize();   //necessary it same as new and delete

 return 1;

}

产生的文件如下。。

<Location>

<North> Pingking</North>

<South>

   <Shanghai>Xujiahui</Shanghai>

</South>

<East>

     <Heilongjiang>harbin,qiqihar</Heilongjiang>

     <Liaoning>Shenyang,Dalian</Liaoning>

</East>

-----------------------------------------------------------------------------------------查找值

访问结点时，如果要读<North>的值，就直接把”North”写进去，返回的就是Pingking了，

要访问<Shanghai>要代入”South\\Shanghai”， 这个和注册表分健值很像

char* GetValueFromXml( char* nodeName)

{// get the value of certain node named nodeName

 // from the xml file

 // the return value 0 represent failure

              char* nodeValue=NULL;

              ::CoInitialize(NULL);

              MSXML2::IXMLDOMDocumentPtr pDoc;

              HRESULT hr = pDoc.CreateInstance(__uuidof(DOMDocument30));

              if(!(SUCCEEDED(hr)))

              {    

                     return nodeValue;

              }  

              hr=pDoc->load("book.xml");

              if(!SUCCEEDED(hr))

              {           

                     MSXML2::IXMLDOMElementPtr pPolicyNode=pDoc->GetdocumentElement();           

                     MSXML2::IXMLDOMElementPtr pSelectNode=pPolicyNode->selectSingleNode(nodeName);       

                     nodeValue =    _com_util::ConvertBSTRToString(pSelectNode->text);             

                     pPolicyNode.Release();

                     pSelectNode.Release();

              }

              pDoc.Release();

              ::CoUninitialize();

              return nodeValue;

}

--------------------------------------------------------------------------------修改XML 文件中的某一个结点的值

访问方法同上

int modify(const char* nodeName,char* nodeValue)//前者为结点名，后者为结点的字串值。

{// modify the value of node named as nodeName

 // the new value is nodeValue

 // if the xml file is not existed then return

 // 0

       ::CoInitialize(NULL);

       MSXML2::IXMLDOMDocumentPtr pDoc;

       HRESULT hr = pDoc.CreateInstance(__uuidof(DOMDocument30));

    int rtval=0;

       if(!(SUCCEEDED(hr)))

       {    

              rtval=0;  

              return rtval;

       }  

       hr=pDoc->load("book.xml");// 文件名。

       if(!SUCCEEDED(hr))

       {

              MSXML2::IXMLDOMElementPtr pPolicyNode=pDoc->GetdocumentElement();           

              MSXML2::IXMLDOMElementPtr 二pSelectNode=pPolicyNode->selectSingleNode(nodeName);

              pSelectNode->Puttext(nodeValue);

              pDoc->save("book.xml");

              pPolicyNode.Release();

              pSelectNode.Release();

              rtval=1;         

       }

       pDoc.Release();

       ::CoUninitialize();

       return rtval;

}

-------------------------------------------------------------------------------------------------删去结点

这个就是一个什么remove 的成员函数就搞定了，和查找的差不多，先找到要删的结点，就行了。。当然删后要保存了，这一点不同，想必都知道。。