cstring 转 utf8

如果原字符是Unicode编码，使用WideCharToMultiBytes，使用UTF8代码页如果是ansi编码的则先使用MultiBytesToWideChar转换为Unicode编码，再按上述操作完成

1. //把utf8转成unicode，再转成cstring  

   void ConvertUTF8ToANSI(char* strUTF8,CString &strANSI)  //  

   {  

       int nLen = ::MultiByteToWideChar(CP_UTF8,MB_ERR_INVALID_CHARS,(LPCTSTR)strUTF8,-1,NULL,0);  //返回需要的unicode长度  

       WCHAR * wszANSI = new WCHAR[nLen+1];  

       memset(wszANSI, 0, nLen * 2 + 2);  

       nLen = MultiByteToWideChar(CP_UTF8, 0, (LPCTSTR)strUTF8, -1, wszANSI, nLen);    //把utf8转成unicode  

         

       nLen = WideCharToMultiByte(CP_ACP, 0, wszANSI, -1, NULL, 0, NULL, NULL);        //得到要的ansi长度  

       char *szANSI=new char[nLen + 1];  

       memset(szANSI, 0, nLen + 1);  

       WideCharToMultiByte (CP_ACP, 0, wszANSI, -1, szANSI, nLen, NULL,NULL);          //把unicode转成ansi  

       strANSI = szANSI;  

       delete wszANSI;  

       delete szANSI;  

   }  

    

    

   void ConvertANSIToUTF8(CString &strANSI)  

   {  

   int nLen = ::MultiByteToWideChar(CP_ACP,MB_ERR_INVALID_CHARS,(LPCTSTR)strANSI,-1,NULL,0);  

   unsigned short * wszUTF_8 = new unsigned short[nLen+1];  

   memset(wszUTF_8, 0, nLen * 2 + 2);  

   nLen = MultiByteToWideChar(CP_ACP, 0, (LPCTSTR)strANSI, -1, wszUTF_8, nLen);  

     

   nLen = WideCharToMultiByte(CP_UTF8, 0, wszUTF_8, -1, NULL, 0, NULL, NULL);  

       char *szUTF8=new char[nLen + 1];  

       memset(szUTF8, 0, nLen + 1);  

       WideCharToMultiByte (CP_UTF8, 0, wszUTF_8, -1, szUTF8, nLen, NULL,NULL);  

   strANSI = szUTF8;  

   delete wszUTF_8;  

   delete szUTF8;  

   }