遞歸掃描根目錄下的所有目錄和發現只有從每個文件夾

Question

這就是我嘗試，但它只有頂級目錄根目錄下只返回最新的文件

if(Directory.Exists("YourPath")) 
foreach (string _tempFiles in Directory.GetDirectories("YourPath") 
         .Select(directory => Directory.GetFiles(directory, "*.*", SearchOption.AllDirectories) 
         .OrderByDescending(File.GetLastWriteTime) 
         .FirstOrDefault())) 

Answer 1

這將返回所有最新的文件每個目錄（包括根）的最新文件：

var rootDirFile = Directory 
    .EnumerateFiles(yourPath, "*.*", SearchOption.TopDirectoryOnly) 
    .OrderByDescending(f => File.GetLastWriteTime(f)) 
    .Take(1); 
var allNewestFilesOfEachFolder = Directory 
    .EnumerateDirectories(yourParth, "*.*", SearchOption.AllDirectories) 
    .Select(d => Directory.EnumerateFiles(d, "*.*") 
     .OrderByDescending(f => File.GetLastWriteTime(f)) 
     .FirstOrDefault()); 
// put both together, the root-file first 
allNewestFilesOfEachFolder = rootDirFile.Concat(allNewestFilesOfEachFolder); 

如果有一個目錄中的文件是null沒有文件，所以文件的數目等於文件夾的數量。

請注意，Linq並不是System.IO的正確工具，因爲錯誤處理很困難。

Answer 2

我寫了一個基本的遞歸函數來處理這個問題：

// Dictionary: 
// Key = The directory name. 
// Value = The most recently modified file for that directory. 
public static Dictionary<string, string> GetNewestFiles(string directory) 
{ 
    return GetNewestFiles(directory, null); 
} 

static Dictionary<string, string> GetNewestFiles(string directory, 
               Dictionary<string, string> dictionary) 
{ 
    if(dictionary == null) 
    dictionary = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase); 

    try 
    { 
    var files = from file in Directory.GetFiles(directory) 
       select new FileInfo(file); 

    var latestFile = files.OrderByDescending(file => { return file.LastWriteTimeUtc; }).FirstOrDefault(); 

    if (latestFile != null) 
     dictionary[latestFile.DirectoryName] = latestFile.FullName; 
    } 
    catch { } 

    foreach (var subDirectory in Directory.GetDirectories(directory)) 
    { 
    try 
    { 
     GetNewestFiles(subDirectory, dictionary); 
    } 
    catch { } 
    } 

    return dictionary; 
} 

，那麼你可以叫它像這樣：

var fileDictionary = GetNewestFiles(@"C:\MyFolder");