C++ writestring 为什么不能写进中文 CStdioFile向无法向文本中写入中文【二】

the start of the file, need to write byte mark
    if(GetPosition() == 0)
    {
     wchar_t cBOM = (wchar_t)UNICODE_BOM;
     CFile::Write(&cBOM, sizeof(wchar_t));
    }
    if (fputws(lpsz, m_pStream) == _TEOF)
     AfxThrowFileException(CFileException::diskFull, _doserrno, m_strFileName);
}
else
{
    USES_CONVERSION;
    WriteAnsiString(CW2A(lpsz));
}
}

void CStdioFileEx::WriteAnsiString(LPCSTR lpsz)
{
ASSERT(lpsz != NULL);

if (lpsz == NULL)
{
    AfxThrowInvalidArgException();
}
if(!m_bIsUnicodeText)
{
    ASSERT(m_pStream != NULL);
    if (fputs(lpsz, m_pStream) == _TEOF)
     AfxThrowFileException(CFileException::diskFull, _doserrno, m_strFileName);
}
else
{
    USES_CONVERSION;
    WriteWideString(CA2W(lpsz));
}
}

UINT CStdioFileEx::PreprocessFlags(const CString& sFilePath, UINT& nOpenFlags)
{
m_bIsUnicodeText = false;

// If we have writeUnicode we must have write or writeRead as well
if (nOpenFlags & CStdioFileEx::modeWriteUnicode)
{
    ASSERT(nOpenFlags & CFile::modeWrite || nOpenFlags & CFile::modeReadWrite);
    m_bIsUnicodeText = true;
}
// If reading in text mode and not creating...
else if (nOpenFlags & CFile::typeText && !(nOpenFlags & CFile::modeCreate) && !(nOpenFlags & CFile::modeWrite ))
{
    m_bIsUnicodeText = IsFileUnicode(sFilePath);
}

//如果要读写Unicode格式的文本文件, 必须切换到typeBinary方式, 因为这会影响fputws/fgetws的工作方式(具体情况参考MSDN)。
if (m_bIsUnicodeText)
{
    nOpenFlags &= ~(CFile::typeText);
    nOpenFlags |= CFile::typeBinary;
}

return nOpenFlags;
}

// Purpose:    Determines whether a file is Unicode by reading the first character and detecting
//       whether it's the Unicode byte marker.
bool CStdioFileEx::IsFileUnicode(const CString& sFilePath)
{
CFile      file;
wchar_t     cFirstChar;
CFileException exFile;

bool      bIsUnicode = false;
// Open file in binary mode and read first character
if (file.Open(sFilePath, CFile::typeBinary | CFile::modeRead, &exFile))
{
    // If byte is Unicode byte-order marker, let's say it's Unicode
    if (file.Read(&cFirstChar, sizeof(wchar_t)) > 0 && cFirstChar == (wchar_t)UNICODE_BOM)
    {
     bIsUnicode = true;
    }

    file.Close();
}
else
{
    // Handle error here if you like
}

return bIsUnicode;
}

unsigned long CStdioFileEx::GetCharCount()
{
int      nCharSize;
unsigned long nByteCount, nCharCount = 0;

if (m_pStream)
{
    // Get size of chars in file
    nCharSize = m_bIsUnicodeText ? sizeof(wchar_t): sizeof(char);

    // If Unicode, remove byte order mark from count
    nByteCount = (unsigned long)GetLength();

    if (m_bIsUnicodeText)
    {
     nByteCount = nByteCount - sizeof(wchar_t);
    }

    // Calc chars
    nCharCount = (nByteCount / nCharSize);
}

return nCharCount;
}