VC++文件监控(一) ReadDirectoryChangesW

From: http://www.cnblogs.com/doublesnke/archive/2011/08/16/2141374.html

VC++实施文件监控：实例和详解

相关帮助: http://hi.baidu.com/jiahaosoft/blog/item/b441d1218eebece0d6cae274.html

我这里只介绍采用ReadDirectoryChangesW对文件目录实施监控

关键代码

CfgdsgDlg * dlg = (CfgdsgDlg*)lparam;

    HANDLE hDir;
    char notify[1024];
    DWORD cbBytes,i;
    char AnsiChar[3];
    wchar_t UnicodeChar[2];
    CString path;

    FILE_NOTIFY_INFORMATION *pnotify=(FILE_NOTIFY_INFORMATION *)notify;
    FILE_NOTIFY_INFORMATION *tmp;

    GetCurrentDirectory(MAX_PATH,path.GetBuffer(MAX_PATH+1));
    hDir = CreateFile( path, FILE_LIST_DIRECTORY,
        FILE_SHARE_READ |
        FILE_SHARE_WRITE |
        FILE_SHARE_DELETE, NULL,
        OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS |
        FILE_FLAG_OVERLAPPED, NULL);
    if (hDir == INVALID_HANDLE_VALUE)
    {

        dlg->m_edit.ReplaceSel( "hDir:INVALID_HANDLE_VALUE\r\n" );
        return 0;
    }

    while (TRUE)
    {
        if (ReadDirectoryChangesW(hDir, &notify, sizeof (notify),
            FALSE, FILE_NOTIFY_CHANGE_FILE_NAME| FILE_NOTIFY_CHANGE_LAST_WRITE,
            &cbBytes, NULL, NULL))
        {

            tmp = pnotify;

            switch (tmp->Action)
            {
            case FILE_ACTION_ADDED:

                dlg->m_edit.ReplaceSel( "Directory/File added （添加文件）- \r\n" );
                break ;
            case FILE_ACTION_REMOVED:
                dlg->m_edit.ReplaceSel( "Directory/File removed （删除文件）- \r\n" );
                break ;
            case FILE_ACTION_MODIFIED:
                dlg->m_edit.ReplaceSel( "Directory/File modified （修改文件内容）- \r\n" );
                break ;
            case FILE_ACTION_RENAMED_OLD_NAME:
                dlg->m_edit.ReplaceSel( "Directory/File old name （修改文件名字）- \r\n" );
                break ;
            case FILE_ACTION_RENAMED_NEW_NAME:
                dlg->m_edit.ReplaceSel( "Directory/File new name - \r\n" );
                break ;
            default :
                break ;
            }
        }
    }

　　

FILE_NOTIFY_INFORMATION //可以确定是那个文件进行的修改

typedef struct _FILE_NOTIFY_INFORMATION {
  DWORD NextEntryOffset;
  DWORD Action;//动作
  DWORD FileNameLength;//文件名字的长度
  WCHAR FileName[1];//文件名字
} FILE_NOTIFY_INFORMATION,
*PFILE_NOTIFY_INFORMATION;

ReadDirectoryChangesW 返回类型(见MSDN)

Value	Meaning
FILE_ACTION_ADDED 0x00000001	The file was added to the directory.
FILE_ACTION_REMOVED 0x00000002	The file was removed from the directory.
FILE_ACTION_MODIFIED 0x00000003	The file was modified. This can be a change in the time stamp or attributes.
FILE_ACTION_RENAMED_OLD_NAME 0x00000004	The file was renamed and this is the old name.
FILE_ACTION_RENAMED_NEW_NAME 0x00000005	The file was renamed and this is the new name.

效果如下：

不足的地方:

只能检测到指定目录和下一级目录，超过目录级数，该函数检测不到。