CRichEditCtrl::SetReadOnly
BOOL SetReadOnly( BOOL bReadOnly = TRUE );

//CRichEditCtrl *pMyRichEditCtrl;
pMyRichEditCtrl->SetReadOnly(TRUE); 
ASSERT(pMyRichEditCtrl->GetStyle() & ES_READONLY);

//CRichEditView * pView ;
pView->GetRichEditCtrl( ).SetReadOnly(TRUE); 
ASSERT(pView->GetRichEditCtrl( ).GetStyle() & ES_READONLY);

class CAboutDlg : public CDialog
{
public:
CAboutDlg();
static DWORD CALLBACK RichEditStreamInCallback(DWORD dwCookie,
  LPBYTE pbBuff, LONG cb, LONG FAR *pcb); 
static DWORD CALLBACK RichEditStreamOutCallback(DWORD dwCookie, 
  LPBYTE pbBuff, LONG cb, LONG FAR *pcb);

boolm_bNewFile;
CString m_strRtfFileName;
HANDLE  m_hFile;
//...............
};

// .cpp
DWORD CALLBACK CAboutDlg::RichEditStreamOutCallback(
      DWORD dwCookie,LPBYTE pbBuff, LONG cb, LONG FAR *pcb)
{
    CAboutDlg* pDlg = reinterpret_cast<CAboutDlg*>(dwCookie); 
    if(pDlg->m_bNewFile)        
    {        
        pDlg->m_bNewFile=false;        
        pDlg->m_hFile = CreateFile(pDlg->m_strRtfFileName,            
         GENERIC_WRITE,FILE_SHARE_WRITE,NULL,CREATE_ALWAYS,0,NULL);        
    }
    if(pDlg->m_hFile == INVALID_HANDLE_VALUE)return 1;
    DWORD bytesWritten;
    WriteFile(pDlg->m_hFile,pbBuff,cb,&bytesWritten,NULL);
    *pcb = bytesWritten;
    return 0;
}
// ----------------------------------------------------------------------------
DWORD CALLBACK CAboutDlg::RichEditStreamInCallback(
      DWORD dwCookie, LPBYTE pbBuff, LONG cb, LONG FAR *pcb)
{
    CAboutDlg* pDlg = reinterpret_cast<CAboutDlg*>(dwCookie);       
    if(pDlg->m_bNewFile)        
    {        
        pDlg->m_bNewFile=false;        
        pDlg->m_hFile = CreateFile(pDlg->m_strRtfFileName,            
            GENERIC_READ,FILE_SHARE_READ,NULL,OPEN_EXISTING,0,NULL);
    }
    if(pDlg->m_hFile == INVALID_HANDLE_VALUE)
    return 1;

    //read some data
    DWORD bytesRead;
    int rt = ReadFile(pDlg->m_hFile,pbBuff,cb,&bytesRead,NULL);
    if(rt == FALSE)
    return 1;

    *pcb = bytesRead; 
    if(bytesRead != (DWORD)cb || bytesRead == 0)        
    {        
        if(pDlg->m_hFile != INVALID_HANDLE_VALUE)           
        {            
            CloseHandle(pDlg->m_hFile);            
            pDlg->m_bNewFile=true;            
        }        
    }    
    return 0;
}
BOOL CAboutDlg::OnInitDialog() 
{
    CDialog::OnInitDialog();
            
    m_strRtfFileName="c:\\initial.rtf";    
    m_bNewFile=true;    
    m_hFile=INVALID_HANDLE_VALUE;
            
    // TODO: Add extra initialization here    
    CRichEditCtrl* pRichEditCtrl = new CRichEditCtrl;    
    pRichEditCtrl->Create(WS_CHILD|WS_BORDER|ES_MULTILINE,CRect(10,10,100,200),this,1);    
    EDITSTREAM es;
            
    es.dwCookie =(DWORD_PTR )this;    
    es.dwError = 0;     
    es.pfnCallback = (EDITSTREAMCALLBACK)RichEditStreamInCallback;    
    pRichEditCtrl->StreamIn(SF_RTF,es);
            
    // Insérer votre traitement ici     
    //    
    //    
    m_strRtfFileName="c:\\other.rtf";   
    es.dwCookie =(DWORD_PTR )this;    
    es.dwError = 0;     
    es.pfnCallback = (EDITSTREAMCALLBACK)RichEditStreamOutCallback;    
    pRichEditCtrl->StreamOut(SF_RTF,es);    

    if(m_hFile != INVALID_HANDLE_VALUE)         
    {         
        CloseHandle(m_hFile);         
        m_bNewFile=true;            
    }    
    pRichEditCtrl->DestroyWindow();   
    delete pRichEditCtrl;
        
    return TRUE;  // return TRUE unless you set the focus to a control    
    // EXCEPTION: OCX Property Pages should return FALSE
}