UTF8和GBK的转换不成功

//UTF8 TO GBK

CString UTF8ToGBK(CString str)

{

 int len=MultiByteToWideChar(CP_UTF8, 0, (LPCTSTR)str, -1, NULL,0);

 WCHAR * wszGBK = new WCHAR[len+1];

 memset(wszGBK, 0, len * 2 + 2);

 MultiByteToWideChar(CP_UTF8, 0, (LPCTSTR)str, -1, wszGBK, len);



 len = WideCharToMultiByte(CP_ACP, 0, wszGBK, -1, NULL, 0, NULL, NULL);

 char *szGBK=new char[len + 1];

 memset(szGBK, 0, len + 1);

 WideCharToMultiByte (CP_ACP, 0, wszGBK, -1, szGBK, len, NULL,NULL);



 CString strResult = szGBK;

 delete[] szGBK;

 delete[] wszGBK;



 return strResult;

}



//GBK TO UTF8

CString GBKToUTF8(CString str)

{

 int len=MultiByteToWideChar(CP_ACP, 0, (LPCTSTR)str, -1, NULL,0);

 WCHAR * wszUtf8 = new WCHAR[len+1];

 memset(wszUtf8, 0, len * 2 + 2);

 MultiByteToWideChar(CP_ACP, 0, (LPCTSTR)str, -1, wszUtf8, len);



 len = WideCharToMultiByte(CP_UTF8, 0, wszUtf8, -1, NULL, 0, NULL, NULL);

 char *szUtf8=new char[len + 1];

 memset(szUtf8, 0, len + 1);

 WideCharToMultiByte (CP_UTF8, 0, wszUtf8, -1, szUtf8, len, NULL,NULL);



 CString strResult = szUtf8;

 delete[] szUtf8;

 delete[] wszUtf8;

 return strResult;

}