下面是B. Clay Shannon的非静态excel文件代码:

class ExcelSearcher
{
    private List<string> _fileNames;

    public ExcelSearcher(List<string> filenames)
    {
        _fileNames = filenames;
    }
    public List<string> GetExcelFiles(string dir, List<string> filenames = null)
    {

        string dirName = dir;
        var dirNames = new List<string>();
        if (filenames != null)
        {
            _fileNames.Concat(filenames);
        }
        try
        {
            foreach (string f in Directory.GetFiles(dirName))
            {
                if (f.ToLower().EndsWith(".xls") || f.ToLower().EndsWith(".xlsx"))
                {
                    _fileNames.Add(f);
                }
            }
            dirNames = Directory.GetDirectories(dirName).ToList();
            foreach (string d in dirNames)
            {
                GetExcelFiles(d, _fileNames);
            }
        }
        catch (Exception ex)
        {
            //Bam
        }
        return _fileNames;
    }

下面是B. Clay Shannon的非静态excel文件代码:

class ExcelSearcher
{
    private List<string> _fileNames;

    public ExcelSearcher(List<string> filenames)
    {
        _fileNames = filenames;
    }
    public List<string> GetExcelFiles(string dir, List<string> filenames = null)
    {

        string dirName = dir;
        var dirNames = new List<string>();
        if (filenames != null)
        {
            _fileNames.Concat(filenames);
        }
        try
        {
            foreach (string f in Directory.GetFiles(dirName))
            {
                if (f.ToLower().EndsWith(".xls") || f.ToLower().EndsWith(".xlsx"))
                {
                    _fileNames.Add(f);
                }
            }
            dirNames = Directory.GetDirectories(dirName).ToList();
            foreach (string d in dirNames)
            {
                GetExcelFiles(d, _fileNames);
            }
        }
        catch (Exception ex)
        {
            //Bam
        }
        return _fileNames;
    }

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];
            }
        }
    }
}

一些很好的答案，但这些答案并没有解决我的问题。

一旦出现文件夹权限问题:“permission Denied”，代码就会失败。这是我用来解决“Permission Denied”问题的方法:

private int counter = 0;

    private string[] MyDirectories = Directory.GetDirectories("C:\\");

    private void ScanButton_Click(object sender, EventArgs e)
    {
        Thread MonitorSpeech = new Thread(() => ScanFiles());
        MonitorSpeech.Start();
    }

    private void ScanFiles()
    {
        string CurrentDirectory = string.Empty;

        while (counter < MyDirectories.Length)
        {
            try
            {
                GetDirectories();
                CurrentDirectory = MyDirectories[counter++];
            }
            catch
            {
                if (!this.IsDisposed)
                {
                    listBox1.Invoke((MethodInvoker)delegate { listBox1.Items.Add("Access Denied to : " + CurrentDirectory); });
                }
            }
        }
    }

    private void GetDirectories()
    {
        foreach (string directory in MyDirectories)
        {
            GetFiles(directory);
        }
    }

    private void GetFiles(string directory)
    {
        try
        {
            foreach (string file in Directory.GetFiles(directory, "*"))
            {
                listBox1.Invoke((MethodInvoker)delegate { listBox1.Items.Add(file); });
            }
        }
        catch
        {
            listBox1.Invoke((MethodInvoker)delegate { listBox1.Items.Add("Access Denied to : " + directory); });
        }
    }

希望这能帮助到其他人。

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;
        }
    }
}

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)
    {

    }
}