我的解决方案基本上是对@Termininja的答案的修改，但我增强了一点，它似乎比公认的答案快5倍以上。

public static void CopyEntireDirectory(string path, string newPath)
{
    Parallel.ForEach(Directory.GetFileSystemEntries(path, "*", SearchOption.AllDirectories)
    ,(fileName) =>
    {
        string output = Regex.Replace(fileName, "^" + Regex.Escape(path), newPath);
        if (File.Exists(fileName))
        {
            Directory.CreateDirectory(Path.GetDirectoryName(output));
            File.Copy(fileName, output, true);
        }
        else
            Directory.CreateDirectory(output);
    });
}

编辑:将@Ahmed Sabry修改为完全并行foreach确实会产生更好的结果，但是代码使用递归函数，在某些情况下并不理想。

public static void CopyEntireDirectory(DirectoryInfo source, DirectoryInfo target, bool overwiteFiles = true)
{
    if (!source.Exists) return;
    if (!target.Exists) target.Create();

    Parallel.ForEach(source.GetDirectories(), (sourceChildDirectory) =>
        CopyEntireDirectory(sourceChildDirectory, new DirectoryInfo(Path.Combine(target.FullName, sourceChildDirectory.Name))));

    Parallel.ForEach(source.GetFiles(), sourceFile =>
        sourceFile.CopyTo(Path.Combine(target.FullName, sourceFile.Name), overwiteFiles));
}

public static class Extensions
{
    public static void Copy(this DirectoryInfo self, DirectoryInfo destination, bool recursively)
    {
        foreach (var file in self.GetFiles())
        {
            file.CopyTo(Path.Combine(destination.FullName, file.Name));
        }

        if (recursively)
        {
            foreach (var directory in self.GetDirectories())
            {
                directory.Copy(destination.CreateSubdirectory(directory.Name), recursively);
            }
        }
    }
}

使用示例:

var sourceDirectory = new DirectoryInfo(@"C:\source");
var destinationDirectory = new DirectoryInfo(@"C:\destination");

if (destinationDirectory.Exists == false)
{
    sourceDirectory.Copy(destinationDirectory, recursively: true);
}

容易得多

private static void CopyFilesRecursively(string sourcePath, string targetPath)
{
    //Now Create all of the directories
    foreach (string dirPath in Directory.GetDirectories(sourcePath, "*", SearchOption.AllDirectories))
    {
        Directory.CreateDirectory(dirPath.Replace(sourcePath, targetPath));
    }

    //Copy all the files & Replaces any files with the same name
    foreach (string newPath in Directory.GetFiles(sourcePath, "*.*",SearchOption.AllDirectories))
    {
        File.Copy(newPath, newPath.Replace(sourcePath, targetPath), true);
    }
}

复制并替换文件夹中的所有文件

        public static void CopyAndReplaceAll(string SourcePath, string DestinationPath, string backupPath)
    {
            foreach (string dirPath in Directory.GetDirectories(SourcePath, "*", SearchOption.AllDirectories))
            {
                Directory.CreateDirectory($"{DestinationPath}{dirPath.Remove(0, SourcePath.Length)}");
                Directory.CreateDirectory($"{backupPath}{dirPath.Remove(0, SourcePath.Length)}");
            }
            foreach (string newPath in Directory.GetFiles(SourcePath, "*.*", SearchOption.AllDirectories))
            {
                if (!File.Exists($"{ DestinationPath}{newPath.Remove(0, SourcePath.Length)}"))
                    File.Copy(newPath, $"{ DestinationPath}{newPath.Remove(0, SourcePath.Length)}");
                else
                    File.Replace(newPath
                        , $"{ DestinationPath}{newPath.Remove(0, SourcePath.Length)}"
                        , $"{ backupPath}{newPath.Remove(0, SourcePath.Length)}", false);
            }
    }

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);
    }
}

我的解决方案基本上是对@Termininja的答案的修改，但我增强了一点，它似乎比公认的答案快5倍以上。

public static void CopyEntireDirectory(string path, string newPath)
{
    Parallel.ForEach(Directory.GetFileSystemEntries(path, "*", SearchOption.AllDirectories)
    ,(fileName) =>
    {
        string output = Regex.Replace(fileName, "^" + Regex.Escape(path), newPath);
        if (File.Exists(fileName))
        {
            Directory.CreateDirectory(Path.GetDirectoryName(output));
            File.Copy(fileName, output, true);
        }
        else
            Directory.CreateDirectory(output);
    });
}

编辑:将@Ahmed Sabry修改为完全并行foreach确实会产生更好的结果，但是代码使用递归函数，在某些情况下并不理想。

public static void CopyEntireDirectory(DirectoryInfo source, DirectoryInfo target, bool overwiteFiles = true)
{
    if (!source.Exists) return;
    if (!target.Exists) target.Create();

    Parallel.ForEach(source.GetDirectories(), (sourceChildDirectory) =>
        CopyEntireDirectory(sourceChildDirectory, new DirectoryInfo(Path.Combine(target.FullName, sourceChildDirectory.Name))));

    Parallel.ForEach(source.GetFiles(), sourceFile =>
        sourceFile.CopyTo(Path.Combine(target.FullName, sourceFile.Name), overwiteFiles));
}