try
{
    if (cbSubFolders.Checked == false)
    {
        string[] files = Directory.GetFiles(folderBrowserDialog1.SelectedPath);
        foreach (string fileName in files)
            ProcessFile(fileName);
    }
    else
    {
        string[] files = Directory.GetFiles(folderBrowserDialog1.SelectedPath, "*.*", SearchOption.AllDirectories);
        foreach (string fileName in files)
            ProcessFile(fileName);
    }
    lblNumberOfFilesDisplay.Enabled = true;
}
catch (UnauthorizedAccessException) { }
finally {}

您将不得不手动执行递归；不要使用AllDirectories-一次查找一个文件夹，然后尝试从子目录中获取文件。未测试，但如下所示（注意使用委托而不是构建数组）：

using System;
using System.IO;
static class Program
{
    static void Main()
    {
        string path = ""; // TODO
        ApplyAllFiles(path, ProcessFile);
    }
    static void ProcessFile(string path) {/* ... */}
    static void ApplyAllFiles(string folder, Action<string> fileAction)
    {
        foreach (string file in Directory.GetFiles(folder))
        {
            fileAction(file);
        }
        foreach (string subDir in Directory.GetDirectories(folder))
        {
            try
            {
                ApplyAllFiles(subDir, fileAction);
            }
            catch
            {
                // swallow, log, whatever
            }
        }
    }
}

由于.NET Standard 2.1（.NET Core 3+、.NET 5+），您现在可以执行以下操作：

var filePaths = Directory.EnumerateFiles(@"C:'my'files", "*.xml", new EnumerationOptions
{
    IgnoreInaccessible = true,
    RecurseSubdirectories = true
});

根据MSDN文档中关于IgnoreInaccessible:

获取或设置一个值，该值指示访问被拒绝时是否跳过文件或目录（例如，UnauthorizedAccessException或SecurityException）。默认值为true。

默认值实际上是真的，但我把它放在这里只是为了显示属性。

同样的过载也可用于DirectoryInfo。

这个简单的函数运行良好，满足了问题的要求。

private List<string> GetFiles(string path, string pattern)
{
    var files = new List<string>();
    var directories = new string[] { };
    try
    {
        files.AddRange(Directory.GetFiles(path, pattern, SearchOption.TopDirectoryOnly));
        directories = Directory.GetDirectories(path);
    }
    catch (UnauthorizedAccessException) { }
    foreach (var directory in directories)
        try
        {
            files.AddRange(GetFiles(directory, pattern));
        }
        catch (UnauthorizedAccessException) { }
    return files;
}

一种简单的方法是使用文件列表和目录队列。它可以保存内存。如果使用递归程序执行相同的任务，则可能引发OutOfMemory异常。输出：添加到列表中的文件按照从上到下（广度优先）的目录树进行组织。

public static List<string> GetAllFilesFromFolder(string root, bool searchSubfolders) {
    Queue<string> folders = new Queue<string>();
    List<string> files = new List<string>();
    folders.Enqueue(root);
    while (folders.Count != 0) {
        string currentFolder = folders.Dequeue();
        try {
            string[] filesInCurrent = System.IO.Directory.GetFiles(currentFolder, "*.*", System.IO.SearchOption.TopDirectoryOnly);
            files.AddRange(filesInCurrent);
        }
        catch {
            // Do Nothing
        }
        try {
            if (searchSubfolders) {
                string[] foldersInCurrent = System.IO.Directory.GetDirectories(currentFolder, "*.*", System.IO.SearchOption.TopDirectoryOnly);
                foreach (string _current in foldersInCurrent) {
                    folders.Enqueue(_current);
                }
            }
        }
        catch {
            // Do Nothing
        }
    }
    return files;
}

步骤：

1. 在队列中登记根
2. 在循环中，将其取消排队，将该目录中的文件添加到列表中，并将子文件夹添加到队列中
3. 重复，直到队列为空

请参阅https://stackoverflow.com/a/10728792/89584用于处理UnauthorizedAccessException问题的解决方案。

如果对GetFiles（）或GetDirectories（）的任何调用都位于具有混合权限的文件夹上，则上述所有解决方案都将丢失文件和/或目录。

这里有一个功能齐全、兼容.NET 2.0的实现

您甚至可以更改生成的文件的List，以跳过FileSystemInfo版本中的目录！

（注意null值！）

public static IEnumerable<KeyValuePair<string, string[]>> GetFileSystemInfosRecursive(string dir, bool depth_first)
{
    foreach (var item in GetFileSystemObjectsRecursive(new DirectoryInfo(dir), depth_first))
    {
        string[] result;
        var children = item.Value;
        if (children != null)
        {
            result = new string[children.Count];
            for (int i = 0; i < result.Length; i++)
            { result[i] = children[i].Name; }
        }
        else { result = null; }
        string fullname;
        try { fullname = item.Key.FullName; }
        catch (IOException) { fullname = null; }
        catch (UnauthorizedAccessException) { fullname = null; }
        yield return new KeyValuePair<string, string[]>(fullname, result);
    }
}
public static IEnumerable<KeyValuePair<DirectoryInfo, List<FileSystemInfo>>> GetFileSystemInfosRecursive(DirectoryInfo dir, bool depth_first)
{
    var stack = depth_first ? new Stack<DirectoryInfo>() : null;
    var queue = depth_first ? null : new Queue<DirectoryInfo>();
    if (depth_first) { stack.Push(dir); }
    else { queue.Enqueue(dir); }
    for (var list = new List<FileSystemInfo>(); (depth_first ? stack.Count : queue.Count) > 0; list.Clear())
    {
        dir = depth_first ? stack.Pop() : queue.Dequeue();
        FileSystemInfo[] children;
        try { children = dir.GetFileSystemInfos(); }
        catch (UnauthorizedAccessException) { children = null; }
        catch (IOException) { children = null; }
        if (children != null) { list.AddRange(children); }
        yield return new KeyValuePair<DirectoryInfo, List<FileSystemInfo>>(dir, children != null ? list : null);
        if (depth_first) { list.Reverse(); }
        foreach (var child in list)
        {
            var asdir = child as DirectoryInfo;
            if (asdir != null)
            {
                if (depth_first) { stack.Push(asdir); }
                else { queue.Enqueue(asdir); }
            }
        }
    }
}

这应该可以回答这个问题。我忽略了遍历子目录的问题，我想你已经明白了。

当然，您不需要有一个单独的方法，但您可能会发现它也是一个有用的地方，可以验证路径是否有效，并处理调用GetFiles（）时可能遇到的其他异常。

希望这能有所帮助。

private string[] GetFiles(string path)
{
    string[] files = null;
    try
    {
       files = Directory.GetFiles(path);
    }
    catch (UnauthorizedAccessException)
    {
       // might be nice to log this, or something ...
    }
    return files;
}
private void Processor(string path, bool recursive)
{
    // leaving the recursive directory navigation out.
    string[] files = this.GetFiles(path);
    if (null != files)
    {
        foreach (string file in files)
        {
           this.Process(file);
        }
    }
    else
    {
       // again, might want to do something when you can't access the path?
    }
}

我更喜欢使用c#框架函数，但我需要的函数将包含在.net framework 5.0中，所以我必须编写它。

// search file in every subdirectory ignoring access errors
    static List<string> list_files(string path)
    {
        List<string> files = new List<string>();
        // add the files in the current directory
        try
        {
            string[] entries = Directory.GetFiles(path);
            foreach (string entry in entries)
                files.Add(System.IO.Path.Combine(path,entry));
        }
        catch 
        { 
        // an exception in directory.getfiles is not recoverable: the directory is not accessible
        }
        // follow the subdirectories
        try
        {
            string[] entries = Directory.GetDirectories(path);
            foreach (string entry in entries)
            {
                string current_path = System.IO.Path.Combine(path, entry);
                List<string> files_in_subdir = list_files(current_path);
                foreach (string current_file in files_in_subdir)
                    files.Add(current_file);
            }
        }
        catch
        {
            // an exception in directory.getdirectories is not recoverable: the directory is not accessible
        }
        return files;
    }

对于那些目标框架在NET 2.1以下的人，只需在nuget上获取Microsoft.IO.Redist。

var filePaths = Directory.EnumerateFiles(@"C:'my'files", "*.xml", new EnumerationOptions
{
    IgnoreInaccessible = true,
    RecurseSubdirectories = true
});