VC UTF8转ANSI

//首先从UTF8转到UNCODE

//再从UNCODE转到ANSI



int ConvUtf8ToAnsi(CString& strSource, CString& strChAnsi)

{  

    if (strSource.GetLength() <= 0)

        return 0;

   

    CString strWChUnicode;



    strSource.TrimLeft();

    strSource.TrimRight();   

    strChAnsi.Empty();



    int iLenByWChNeed = MultiByteToWideChar(CP_UTF8, 0,

                                            strSource.GetBuffer(0),

                                            strSource.GetLength(), //MultiByteToWideChar

                                            NULL, 0);



    int iLenByWchDone = MultiByteToWideChar(CP_UTF8, 0,

                                            strSource.GetBuffer(0),

                                            strSource.GetLength(),

                                            (LPWSTR)strWChUnicode.GetBuffer(iLenByWChNeed * 2),

                                            iLenByWChNeed); //MultiByteToWideChar

   

    strWChUnicode.ReleaseBuffer(iLenByWchDone * 2);



    int iLenByChNeed  = WideCharToMultiByte(CP_ACP, 0,

                                            (LPCWSTR)strWChUnicode.GetBuffer(0),

                                            iLenByWchDone,

                                            NULL, 0,

                                            NULL, NULL); 

   

    int iLenByChDone  = WideCharToMultiByte(CP_ACP, 0,

                                            (LPCWSTR)strWChUnicode.GetBuffer(0),

                                            iLenByWchDone,

                                            strChAnsi.GetBuffer(iLenByChNeed),

                                            iLenByChNeed,

                                            NULL, NULL);



    strChAnsi.ReleaseBuffer(iLenByChDone);

   

    if (iLenByWChNeed != iLenByWchDone || iLenByChNeed != iLenByChDone)

        return 1;



    return 0;   

}