递归复制文件夹而不递归，以避免堆栈溢出。

public static void CopyDirectory(string source, string target)
{
    var stack = new Stack<Folders>();
    stack.Push(new Folders(source, target));

    while (stack.Count > 0)
    {
        var folders = stack.Pop();
        Directory.CreateDirectory(folders.Target);
        foreach (var file in Directory.GetFiles(folders.Source, "*.*"))
        {
            File.Copy(file, Path.Combine(folders.Target, Path.GetFileName(file)));
        }

        foreach (var folder in Directory.GetDirectories(folders.Source))
        {
            stack.Push(new Folders(folder, Path.Combine(folders.Target, Path.GetFileName(folder))));
        }
    }
}

public class Folders
{
    public string Source { get; private set; }
    public string Target { get; private set; }

    public Folders(string source, string target)
    {
        Source = source;
        Target = target;
    }
}

嗯，我想我误解了这个问题，但我要冒这个险。下面这个简单的方法有什么问题?

public static void CopyFilesRecursively(DirectoryInfo source, DirectoryInfo target) {
    foreach (DirectoryInfo dir in source.GetDirectories())
        CopyFilesRecursively(dir, target.CreateSubdirectory(dir.Name));
    foreach (FileInfo file in source.GetFiles())
        file.CopyTo(Path.Combine(target.FullName, file.Name));
}

由于这篇文章为一个同样简单的问题提供了如此简单的答案，获得了令人印象深刻的反对票，让我补充一个解释。请在投反对票前阅读这篇文章。

首先，这段代码并不打算作为问题中代码的直接替换。这只是为了说明。

microsoft . visualbasic . devices . computer . filesystm . copydirectory执行一些附加的正确性测试(例如，源和目标是否为有效目录，源是否为目标的父目录等)，这些测试在这个答案中是缺失的。该代码可能也更加优化了。

也就是说，代码运行良好。它(几乎完全相同)已经在一个成熟的软件中使用多年了。除了所有IO处理固有的变化无常(例如，如果用户在代码写入USB驱动器时手动拔出USB驱动器会发生什么?)，没有已知的问题。

特别地，我想指出这里使用递归绝对不是问题。无论是在理论上(概念上，这是最优雅的解决方案)还是在实践中:这段代码都不会溢出堆栈。这个堆栈足够大，甚至可以处理嵌套很深的文件层次结构。早在堆栈空间成为问题之前，文件夹路径长度限制就开始生效了。

请注意，恶意用户可能会通过使用每个字母嵌套很深的目录来打破这一假设。我还没试过。但是为了说明这一点:为了使这段代码在典型的计算机上溢出，目录必须嵌套几千次。这是不现实的情况。

抱歉之前的代码，它仍然有bug:((成为最快枪问题的猎物)。这里是测试和工作。键是SearchOption。AllDirectories，这消除了显式递归的需要。

string path = "C:\\a";
string[] dirs = Directory.GetDirectories(path, "*.*", SearchOption.AllDirectories);
string newpath = "C:\\x";
try
{
    Directory.CreateDirectory(newpath);
}
catch (IOException ex)
{
    Console.WriteLine(ex.Message);
}
for (int j = 0; j < dirs.Length; j++)
{
    try
    {
        Directory.CreateDirectory(dirs[j].Replace(path, newpath));
    }
    catch (IOException ex)
    {
        Console.WriteLine(ex.Message);
    }
}

string[] files = Directory.GetFiles(path, "*.*", SearchOption.AllDirectories);
for (int j = 0; j < files.Length; j++)            
{
    try
    {
        File.Copy(files[j], files[j].Replace(path, newpath));
    }
    catch (IOException ex)
    {
        Console.WriteLine(ex.Message);
    }
}

对于UWP和Winui 3 (WindowsAppSdk)使用Async API:

public async Task CopyAsync(StorageFolder source, StorageFolder dest)
{
    foreach (var item in await source.GetItemsAsync())

        if (item is StorageFile file)
            await file.CopyAsync(dest);

        else if (item is StorageFolder folder)
            await CopyAsync(folder, await dest.CreateFolderAsync(folder.Name, CreationCollisionOption.OpenIfExists));
}

复制自MSDN:

using System;
using System.IO;

class CopyDir
{
    public static void Copy(string sourceDirectory, string targetDirectory)
    {
        DirectoryInfo diSource = new DirectoryInfo(sourceDirectory);
        DirectoryInfo diTarget = new DirectoryInfo(targetDirectory);

        CopyAll(diSource, diTarget);
    }

    public static void CopyAll(DirectoryInfo source, DirectoryInfo target)
    {
        Directory.CreateDirectory(target.FullName);

        // Copy each file into the new directory.
        foreach (FileInfo fi in source.GetFiles())
        {
            Console.WriteLine(@"Copying {0}\{1}", target.FullName, fi.Name);
            fi.CopyTo(Path.Combine(target.FullName, fi.Name), true);
        }

        // Copy each subdirectory using recursion.
        foreach (DirectoryInfo diSourceSubDir in source.GetDirectories())
        {
            DirectoryInfo nextTargetSubDir =
                target.CreateSubdirectory(diSourceSubDir.Name);
            CopyAll(diSourceSubDir, nextTargetSubDir);
        }
    }

    public static void Main()
    {
        string sourceDirectory = @"c:\sourceDirectory";
        string targetDirectory = @"c:\targetDirectory";

        Copy(sourceDirectory, targetDirectory);
    }

    // Output will vary based on the contents of the source directory.
}

比任何代码都好(使用递归扩展DirectoryInfo的方法)

public static bool CopyTo(this DirectoryInfo source, string destination)
    {
        try
        {
            foreach (string dirPath in Directory.GetDirectories(source.FullName))
            {
                var newDirPath = dirPath.Replace(source.FullName, destination);
                Directory.CreateDirectory(newDirPath);
                new DirectoryInfo(dirPath).CopyTo(newDirPath);
            }
            //Copy all the files & Replaces any files with the same name
            foreach (string filePath in Directory.GetFiles(source.FullName))
            {
                File.Copy(filePath, filePath.Replace(source.FullName,destination), true);
            }
            return true;
        }
        catch (IOException exp)
        {
            return false;
        }
    }