一个非常简单的解决方案，返回一个文件列表。

    public static List<string> AllFilesInFolder(string folder)
    {
        var result = new List<string>();

        foreach (string f in Directory.GetFiles(folder))
        {
            result.Add(f);
        }

        foreach (string d in Directory.GetDirectories(folder))
        {
            result.AddRange(AllFilesInFolder(d));
        }

        return result;
    }

IEnumerable<string> GetFilesFromDir(string dir) =>
 Directory.EnumerateFiles(dir).Concat(
 Directory.EnumerateDirectories(dir)
          .SelectMany(subdir => GetFilesFromDir(subdir)));

简单的解决方案

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);

注意。net 4.0中内置了基于迭代器的(而不是基于数组的)文件函数:

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

现在我会使用如下的方法;如果你不能访问单个子目录，那么内置的递归方法很容易崩溃…;Queue<string>的使用避免了太多的调用堆栈递归，迭代器块避免了我们拥有一个巨大的数组。

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];
            }
        }
    }
}

Directory.GetFiles("C:\\", "*.*", SearchOption.AllDirectories)

为了避免unauthoredaccessexception，我使用:

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;
        }
    }
}