平台为win32+duilib，其他环境类似。 static DWORD CALLBACK streamInCallback(DWORD_PTR dwCookie, LPBYTE pbBuff, LONG cb, LONG *pcb)
{
    ReadFile((HANDLE)dwCookie, pbBuff, cb, (LPDWORD)pcb, NULL);//读取数据
    return 0;
} BOOL ReadFileByStreamIn(CRichEditUI* hRichEdit, LPCTSTR pszFileName)
{
    HRESULT hr;     HANDLE hFile = CreateFile(pszFileName, GENERIC_READ, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
    if (hFile == INVALID_HANDLE_VALUE)
        return FALSE;     EDITSTREAM es;
    es.dwCookie = (DWORD_PTR)hFile;
    es.pfnCallback = streamInCallback;     hRichEdit->SetSel(0, -1);
    DWORD dwStart, dwEnd;
    hRichEdit->GetSel((long&)dwStart, (long&)dwEnd);
    hRichEdit->SetSel(dwEnd + 1, dwEnd + 1);
    //hRichEdit->ReplaceSel(L" ", TRUE);     CDuiString strFileName(pszFileName);
    CDuiString strExt = strFileName.Right(4);
    if (strExt == _T(".txt"))
        hr = hRichEdit->StreamIn(SF_TEXT | SFF_SELECTION, es);
    else if (strExt == _T(".rtf"))
        hr = hRichEdit->StreamIn(SF_RTF | SFF_SELECTION, es);     CloseHandle(hFile);
    if (FAILED(hr))
    {
        return FALSE;
    }
    return TRUE;
} 写入文本可以此类推。