C# DirectoryInfo.OrderByDescending方法代码示例

        /// <summary>
        /// Проверка существования папки для хранения лог-файлов
        /// </summary>
        private static void CheckFolderExists()
        {
            //Генерируем путь для лог-файлов и кешируем в перменную FolderPath
            FolderPath = Path.Combine(
                Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), //%user%/AppData/Roaming
                "Gemino/Logs" //Папка лог-файлов
                );

            //если папка еще не создана
            if (!Directory.Exists(FolderPath)) {
                //создаем по кешированному пути
                Directory.CreateDirectory(FolderPath);
            } else { //если создана
                //получаем список файлов
                var files = new DirectoryInfo(FolderPath).GetFiles();
                //сортируем по дате создания и пропускаем первые 3 файла
                foreach (var file in files.OrderByDescending(x => x.CreationTime).Skip(3))
                    //4-й файл удаляется как самый старый
                    file.Delete();
            }
        }

        /// <summary>
        /// Gets all files from the specified folder
        /// </summary>
        /// <param name="folder">which folder</param>
        /// <param name="order">sort order</param>
        /// <returns>list of all files</returns>
        private List<FileInfo> getAllFiles(String folder, SortOrder order)
        {
            var retVal = new List<FileInfo>();

            if (Directory.Exists(folder))
            {
                var fileInfo = new DirectoryInfo(folder).GetFiles();

                switch (order)
                {
                    case SortOrder.DateDescending:
                        retVal = fileInfo.OrderByDescending(f => f.LastWriteTime).ToList();
                        break;

                    case SortOrder.DateAscending:
                        retVal = fileInfo.OrderBy(f => f.LastWriteTime).ToList();
                        break;

                    case SortOrder.AtoZ:
                        retVal = fileInfo.OrderBy(f => f.Name).ToList();
                        break;

                    case SortOrder.ZtoA:
                        retVal = fileInfo.OrderByDescending(f => f.Name).ToList();
                        break;

                    default:
                        retVal = fileInfo.ToList();
                        break;
                }
            }

            return retVal;
        }

        /// <summary>
        ///     Gets the previous data file.
        /// </summary>
        /// <param name="name">The name.</param>
        /// <returns></returns>
        /// <exception cref="System.IO.FileNotFoundException">
        ///     Attempts to locate the newest file in the list of parsed data files
        ///     returned null.
        /// </exception>
        private static FileSystemInfo GetPreviousDataFile(string name)
        {
            Debug.Assert(!string.IsNullOrWhiteSpace(name), "The file name cannot be null or empty.");

            string searchPattern = string.Format("{0}*", name);
            IEnumerable<FileSystemInfo> fileInfo = new DirectoryInfo(DataPath).GetFileSystemInfos(searchPattern, SearchOption.TopDirectoryOnly);

            if (!fileInfo.Any())
            {
                return null;
            }

            // Get the newest file in the list
            FileSystemInfo newestFile = fileInfo.OrderByDescending(f => f.CreationTime).FirstOrDefault();

            if (newestFile == null)
            {
                throw new FileNotFoundException("Attempts to locate the newest file in the list of parsed data files returned null.");
            }

            return newestFile;
        }

        private void updateLatestIntelFiles()
        {
            if (LastIntelReported > (DateTime.Now.AddMilliseconds(-1 * timerFileDiscover.Interval))) return; //If intel has been reported recently, we don't need to recheck.
            if (DateTime.UtcNow.TimeOfDay > new TimeSpan(10, 59, 00) && DateTime.UtcNow.TimeOfDay < new TimeSpan(11, 05, 00))
            {
                setState(STATE.DOWNTIME);
                appendText("Downtime Detected.  Waiting for new chat logs to be created.");
            }
            if (state == STATE.RUNNING)
            {
                appendVerbose("Sending heartbeat.");
                ReportIntel(string.Empty, "Running");
            }
            appendVerbose("Updating chatlog file list.");
            string oldfiles = string.Empty;
            foreach (FileInfo fi in roomToFile.Values)
                oldfiles += fi.Name + ", ";

            string report = string.Empty;
            foreach (String roomName in Configuration.RoomsToMonitor)
            {
                Debug.WriteLine("KIU Checking for : " + roomName);

                FileInfo[] files = new DirectoryInfo(Configuration.LogDirectory)
                        .GetFiles(roomName + "_*.txt", SearchOption.TopDirectoryOnly);
                FileInfo fi = files.OrderByDescending(f => f.LastWriteTime).FirstOrDefault();

                if (fi == null)
                {
                    continue;
                }

                Debug.WriteLine("KIU Latest: " + fi);

                // Check if eve has opened this file -> Eve is running and user has joined channel
                Boolean inUse = false;
                try
                {
                    FileStream fs = fi.Open(FileMode.Open, FileAccess.Read, FileShare.None);
                    fs.Close();
                }
                catch
                {
                    inUse = true;
                }

                if (!inUse)
                {
                    Debug.WriteLine("KIU Skipping: " + fi);
                    continue;
                }

                Debug.WriteLine("KIU Using: " + fi);
                roomToFile[roomName] = fi;
                report += fi.Name + "\r\n";
            }

            // Clear offset list of old files if necessary.
            List<FileInfo> deletethese = new List<FileInfo>();
            foreach (FileInfo fi in fileToOffset.Keys)
                if (!roomToFile.ContainsValue(fi)) deletethese.Add(fi);
            foreach (FileInfo fi in deletethese)
                fileToOffset.Remove(fi);

            // If a new file is created, recheck to make sure we have the most up to date log files.
            FileSystemWatcher watcher = new FileSystemWatcher(Configuration.LogDirectory);
            watcher.NotifyFilter = NotifyFilters.CreationTime;
            watcher.Created += new FileSystemEventHandler(FileCreated);
            watcher.EnableRaisingEvents = true;

            string newfiles = string.Empty;
            foreach (FileInfo fi in roomToFile.Values)
                newfiles += fi.Name + ", ";
            if (!newfiles.Equals(oldfiles))
            {
                if (newfiles.Length > 2) newfiles = newfiles.Substring(0, newfiles.Length - 2); // trim the last comma and space
                if (oldfiles.Length > 2) oldfiles = oldfiles.Substring(0, oldfiles.Length - 2); // trim the last comma and space
                if (state == STATE.RUNNING || state == STATE.DOWNTIME) appendText(string.Format("Intel Files Changed. Old Files: {0}, New Files: {1}", oldfiles, newfiles));
                if (state == STATE.DOWNTIME) setState(STATE.START);
            }
            lblMonitoringFiles.Invoke(new MethodInvoker(() => lblMonitoringFiles.Text = report));
        }