How to recursively list all the files in a directory in C#?

Question

How to recursively list all the files in a directory and child directories in C#?

Answer 1

To avoid the UnauthorizedAccessException, I use:

var files = GetFiles(@"C:\", "*.*", SearchOption.AllDirectories);
foreach (var file in files)
{
    Console.WriteLine($"{file}");
}

public static IEnumerable<string> GetFiles(string path, string searchPattern, SearchOption searchOption)
{
    var foldersToProcess = new List<string>()
    {
        path
    };

    while (foldersToProcess.Count > 0)
    {
        string folder = foldersToProcess[0];
        foldersToProcess.RemoveAt(0);

        if (searchOption.HasFlag(SearchOption.AllDirectories))
        {
            //get subfolders
            try
            {
                var subfolders = Directory.GetDirectories(folder);
                foldersToProcess.AddRange(subfolders);
            }
            catch (Exception ex)
            {
                //log if you're interested
            }
        }

        //get files
        var files = new List<string>();
        try
        {
            files = Directory.GetFiles(folder, searchPattern, SearchOption.TopDirectoryOnly).ToList();
        }
        catch (Exception ex)
        {
            //log if you're interested
        }

        foreach (var file in files)
        {
            yield return file;
        }
    }
}

Answer 2

Short and simple solution

string dir = @"D:\PATH";

DateTime from_date = DateTime.Now.Date;
DateTime to_date = DateTime.Now.Date.AddHours(23);
var files = Directory.EnumerateFiles(dir, "*.*",SearchOption.AllDirectories).Select(i=>new FileInfo(i))
.Where(file=>file.LastWriteTime >= from_date && file.LastWriteTime <= to_date);
foreach(var fl in files)
    Console.WriteLine(fl.FullName);

Answer 3

A simple and clean solution

/// <summary>
/// Scans a folder and all of its subfolders recursively, and updates the List of files
/// </summary>
/// <param name="sFullPath">Full path of the folder</param>
/// <param name="files">The list, where the output is expected</param>
internal static void EnumerateFiles(string sFullPath, List<FileInfo> fileInfoList)
{
    try
    {
        DirectoryInfo di = new DirectoryInfo(sFullPath);
        FileInfo[] files = di.GetFiles();

        foreach (FileInfo file in files)
            fileInfoList.Add(file);

        //Scan recursively
        DirectoryInfo[] dirs = di.GetDirectories();
        if (dirs == null || dirs.Length < 1)
            return;
        foreach (DirectoryInfo dir in dirs)
            EnumerateFiles(dir.FullName, fileInfoList);

    }
    catch (Exception ex)
    {
        Logger.Write("Exception in Helper.EnumerateFiles", ex);
    }
}

Answer 4

Note that in .NET 4.0 there are (supposedly) iterator-based (rather than array-based) file functions built in:

foreach (string file in Directory.EnumerateFiles(path, "*.*", SearchOption.AllDirectories))
{
    Console.WriteLine(file);
}

At the moment I'd use something like below; the inbuilt recursive method breaks too easily if you don't have access to a single sub-dir...; the Queue<string> usage avoids too much call-stack recursion, and the iterator block avoids us having a huge array.

static void Main() {
    foreach (string file in GetFiles(SOME_PATH)) {
        Console.WriteLine(file);
    }
}

static IEnumerable<string> GetFiles(string path) {
    Queue<string> queue = new Queue<string>();
    queue.Enqueue(path);
    while (queue.Count > 0) {
        path = queue.Dequeue();
        try {
            foreach (string subDir in Directory.GetDirectories(path)) {
                queue.Enqueue(subDir);
            }
        }
        catch(Exception ex) {
            Console.Error.WriteLine(ex);
        }
        string[] files = null;
        try {
            files = Directory.GetFiles(path);
        }
        catch (Exception ex) {
            Console.Error.WriteLine(ex);
        }
        if (files != null) {
            for(int i = 0 ; i < files.Length ; i++) {
                yield return files[i];
            }
        }
    }
}

Answer 5

Listing files and folders to model, custom implementation.
This creates a full listing of all files and folders starting from your start directory.

public class DirOrFileModel
    {
        #region Private Members

        private string _name;
        private string _location;
        private EntryType _entryType;

        #endregion

        #region Bindings

        public string Name
        {
            get { return _name; }
            set
            {
                if (value == _name) return;
                _name = value;
            }
        }

        public string Location
        {
            get { return _location; }
            set
            {
                if (value == _location) return;
                _location = value;
            }
        }

        public EntryType EntryType
        {
            get { return _entryType; }
            set
            {
                if (value == _entryType) return;
                _entryType = value;
            }
        }

        public ObservableCollection<DirOrFileModel> Entries { get; set; }

        #endregion

        #region Constructor

        public DirOrFileModel()
        {
            Entries = new ObservableCollection<DirOrFileModel>();
        }

        #endregion
    }

    public enum EntryType
    {
        Directory = 0,
        File = 1
    }

Method:

 static DirOrFileModel DirSearch(DirOrFileModel startDir)
        {
            var currentDir = startDir;
            try
            {
                foreach (string d in Directory.GetDirectories(currentDir.Location))
                {
                    var newDir = new DirOrFileModel
                    {
                        EntryType = EntryType.Directory,
                        Location = d,
                        Name = Path.GetFileName(d)
                    };
                    currentDir.Entries.Add(newDir);

                    DirSearch(newDir);
                }

                foreach (string f in Directory.GetFiles(currentDir.Location))
                {
                    var newFile = new DirOrFileModel
                    {
                        EntryType = EntryType.File,
                        Location = f,
                        Name = Path.GetFileNameWithoutExtension(f)
                    };
                    currentDir.Entries.Add(newFile);
                }

            }
            catch (Exception excpt)
            {
                Console.WriteLine(excpt.Message);
            }
            return startDir;
        }

Usage:

var dir = new DirOrFileModel
            {
                Name = "C",
                Location = @"C:\",
                EntryType = EntryType.Directory
            };

            dir = DirSearch(dir);

Answer 6

private void GetFiles(DirectoryInfo dir, ref List<FileInfo> files)
{
    try
    {
        files.AddRange(dir.GetFiles());
        DirectoryInfo[] dirs = dir.GetDirectories();
        foreach (var d in dirs)
        {
            GetFiles(d, ref files);
        }
    }
    catch (Exception e)
    {

    }
}