.NET을 사용하고 루핑하지 않고 디렉토리에서 최신 파일을 찾는 방법은 무엇입니까?

.NET을 사용하고 루핑하지 않고 디렉토리에서 최신 파일을 찾는 방법은 무엇입니까?

---

디렉토리에서 가장 최근에 수정 된 파일을 찾아야합니다.

폴더의 모든 파일을 반복하고 비교할 수 File.GetLastWriteTime있지만 반복하지 않고이를 수행하는 더 좋은 방법이 있습니까?

---

이런 식으로 ...

var directory = new DirectoryInfo("C:\\MyDirectory");
var myFile = (from f in directory.GetFiles()
             orderby f.LastWriteTime descending
             select f).First();

// or...
var myFile = directory.GetFiles()
             .OrderByDescending(f => f.LastWriteTime)
             .First();

---

재귀 적으로 검색하려면이 아름다운 코드를 사용할 수 있습니다.

public static FileInfo GetNewestFile(DirectoryInfo directory) {
   return directory.GetFiles()
       .Union(directory.GetDirectories().Select(d => GetNewestFile(d)))
       .OrderByDescending(f => (f == null ? DateTime.MinValue : f.LastWriteTime))
       .FirstOrDefault();                        
}

다음과 같이 부르십시오.

FileInfo newestFile = GetNewestFile(new DirectoryInfo(@"C:\directory\"));

그리고 그게 다야. FileInfo인스턴스가 있거나 null디렉토리가 비어있는 경우를 리턴합니다 .

---

위의 첫 번째 패턴을 확장하여 특정 패턴을 검색하려면 다음 코드를 사용할 수 있습니다.

string pattern = "*.txt";
var dirInfo = new DirectoryInfo(directory);
var file = (from f in dirInfo.GetFiles(pattern) orderby f.LastWriteTime descending select f).First();

---

비 LINQ 버전 :

/// <summary>
/// Returns latest writen file from the specified directory.
/// If the directory does not exist or doesn't contain any file, DateTime.MinValue is returned.
/// </summary>
/// <param name="directoryInfo">Path of the directory that needs to be scanned</param>
/// <returns></returns>
private static DateTime GetLatestWriteTimeFromFileInDirectory(DirectoryInfo directoryInfo)
{
    if (directoryInfo == null || !directoryInfo.Exists)
        return DateTime.MinValue;

    FileInfo[] files = directoryInfo.GetFiles();
    DateTime lastWrite = DateTime.MinValue;

    foreach (FileInfo file in files)
    {
        if (file.LastWriteTime > lastWrite)
        {
            lastWrite = file.LastWriteTime;
        }
    }

    return lastWrite;
}

/// <summary>
/// Returns file's latest writen timestamp from the specified directory.
/// If the directory does not exist or doesn't contain any file, null is returned.
/// </summary>
/// <param name="directoryInfo">Path of the directory that needs to be scanned</param>
/// <returns></returns>
private static FileInfo GetLatestWritenFileFileInDirectory(DirectoryInfo directoryInfo)
{
    if (directoryInfo == null || !directoryInfo.Exists)
        return null;

    FileInfo[] files = directoryInfo.GetFiles();
    DateTime lastWrite = DateTime.MinValue;
    FileInfo lastWritenFile = null;

    foreach (FileInfo file in files)
    {
        if (file.LastWriteTime > lastWrite)
        {
            lastWrite = file.LastWriteTime;
            lastWritenFile = file;
        }
    }
    return lastWritenFile;
}

---

조금 늦었지만 ...

코드가 작동하지 않으므로 list<FileInfo> lastUpdateFile = null;나중에 lastUpdatedFile.Add(file);NullReference 예외가 발생합니다. 작업 버전은 다음과 같아야합니다.

private List<FileInfo> GetLastUpdatedFileInDirectory(DirectoryInfo directoryInfo)
{
    FileInfo[] files = directoryInfo.GetFiles();
    List<FileInfo> lastUpdatedFile = new List<FileInfo>();
    DateTime lastUpdate = DateTime.MinValue;
    foreach (FileInfo file in files)
    {
        if (file.LastAccessTime > lastUpdate)
        {
            lastUpdatedFile.Add(file);
            lastUpdate = file.LastAccessTime;
        }
    }

    return lastUpdatedFile;
}

감사

---

Short and simple:

new DirectoryInfo(path).GetFiles().OrderByDescending(o => o.LastWriteTime).FirstOrDefault();

---

You can react to new file activity with FileSystemWatcher.

---

Here's a version that gets the most recent file from each subdirectory

List<string> reports = new List<string>();    
DirectoryInfo directory = new DirectoryInfo(ReportsRoot);
directory.GetFiles("*.xlsx", SearchOption.AllDirectories).GroupBy(fl => fl.DirectoryName)
.ForEach(g => reports.Add(g.OrderByDescending(fi => fi.LastWriteTime).First().FullName));

---

Another approach if you are using Directory.EnumerateFiles and want to read files in latest modified by first.

foreach (string file in Directory.EnumerateFiles(fileDirectory, fileType).OrderByDescending(f => new FileInfo(f).LastWriteTime))

}

---

private List<FileInfo> GetLastUpdatedFileInDirectory(DirectoryInfo directoryInfo)
{
    FileInfo[] files = directoryInfo.GetFiles();
    List<FileInfo> lastUpdatedFile = null;
    DateTime lastUpdate = new DateTime(1, 0, 0);
    foreach (FileInfo file in files)
    {
        if (file.LastAccessTime > lastUpdate)
        {
            lastUpdatedFile.Add(file);
            lastUpdate = file.LastAccessTime;
        }
    }

    return lastUpdatedFile;
}

---

I do this is a bunch of my apps and I use a statement like this:

  var inputDirectory = new DirectoryInfo("\\Directory_Path_here");
  var myFile = inputDirectory.GetFiles().OrderByDescending(f => f.LastWriteTime).First();

From here you will have the filename for the most recently saved/added/updated file in the Directory of the "inputDirectory" variable. Now you can access it and do what you want with it.

Hope that helps.

참고URL : https://stackoverflow.com/questions/1179970/how-to-find-the-most-recent-file-in-a-directory-using-net-and-without-looping