Copy the entire contents of a directory in C#

Question

I want to copy the entire contents of a directory from one location to another in C#.

There doesn't appear to be a way to do this using System.IO classes without lots of recursion.

There is a method in VB that we can use if we add a reference to Microsoft.VisualBasic:

new Microsoft.VisualBasic.Devices.Computer().
    FileSystem.CopyDirectory( sourceFolder, outputFolder );

This seems like a rather ugly hack. Is there a better way?

Answer 1

Use this class.

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

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

        foreach (var sourceFile in source.GetFiles())
            sourceFile.CopyTo(Path.Combine(target.FullName, sourceFile.Name), overwiteFiles);
    }
    public static void CopyTo(this DirectoryInfo source, string target, bool overwiteFiles = true)
    {
        CopyTo(source, new DirectoryInfo(target), overwiteFiles);
    }
}

Answer 2

Copied from 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.
}

Answer 3

This site always have helped me out a lot, and now it's my turn to help the others with what I know.

I hope that my code below be useful for someone.

string source_dir = @"E:\";
string destination_dir = @"C:\";

// substring is to remove destination_dir absolute path (E:\).

// Create subdirectory structure in destination    
    foreach (string dir in System.IO.Directory.GetDirectories(source_dir, "*", System.IO.SearchOption.AllDirectories))
    {
        System.IO.Directory.CreateDirectory(System.IO.Path.Combine(destination_dir, dir.Substring(source_dir.Length + 1)));
        // Example:
        //     > C:\sources (and not C:\E:\sources)
    }

    foreach (string file_name in System.IO.Directory.GetFiles(source_dir, "*", System.IO.SearchOption.AllDirectories))
    {
        System.IO.File.Copy(file_name, System.IO.Path.Combine(destination_dir, file_name.Substring(source_dir.Length + 1)));
    }

Answer 4

Hmm, I think I misunderstand the question but I'm going to risk it. What's wrong with the following straightforward method?

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));
}

EDIT Since this posting has garnered an impressive number of downvotes for such a simple answer to an equally simple question, let me add an explanation. Please read this before downvoting.

First of all, this code is not intendend as a drop-in replacement to the code in the question. It is for illustration purpose only.

Microsoft.VisualBasic.Devices.Computer.FileSystem.CopyDirectory does some additional correctness tests (e.g. whether the source and target are valid directories, whether the source is a parent of the target etc.) that are missing from this answer. That code is probably also more optimized.

That said, the code works well. It has (almost identically) been used in a mature software for years. Apart from the inherent fickleness present with all IO handlings (e.g. what happens if the user manually unplugs the USB drive while your code is writing to it?), there are no known problems.

In particular, I’d like to point out that the use of recursion here is absolutely not a problem. Neither in theory (conceptually, it’s the most elegant solution) nor in practice: this code will not overflow the stack. The stack is large enough to handle even deeply nested file hierarchies. Long before stack space becomes a problem, the folder path length limitation kicks in.

Notice that a malicious user might be able to break this assumption by using deeply-nested directories of one letter each. I haven’t tried this. But just to illustrate the point: in order to make this code overflow on a typical computer, the directories would have to be nested a few thousand times. This is simply not a realistic scenario.

Answer 5

Better than any code (extension method to DirectoryInfo with recursion)

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;
        }
    }

Answer 6

Here's a utility class I've used for IO tasks like this.

using System;
using System.Runtime.InteropServices;

namespace MyNameSpace
{
    public class ShellFileOperation
    {
        private static String StringArrayToMultiString(String[] stringArray)
        {
            String multiString = "";

            if (stringArray == null)
                return "";

            for (int i=0 ; i<stringArray.Length ; i++)
                multiString += stringArray[i] + '\0';

            multiString += '\0';

            return multiString;
        }

        public static bool Copy(string source, string dest)
        {
            return Copy(new String[] { source }, new String[] { dest });
        }

        public static bool Copy(String[] source, String[] dest)
        {
            Win32.SHFILEOPSTRUCT FileOpStruct = new Win32.SHFILEOPSTRUCT();

            FileOpStruct.hwnd = IntPtr.Zero;
            FileOpStruct.wFunc = (uint)Win32.FO_COPY;

            String multiSource = StringArrayToMultiString(source);
            String multiDest = StringArrayToMultiString(dest);
            FileOpStruct.pFrom = Marshal.StringToHGlobalUni(multiSource);
            FileOpStruct.pTo = Marshal.StringToHGlobalUni(multiDest);

            FileOpStruct.fFlags = (ushort)Win32.ShellFileOperationFlags.FOF_NOCONFIRMATION;
            FileOpStruct.lpszProgressTitle = "";
            FileOpStruct.fAnyOperationsAborted = 0;
            FileOpStruct.hNameMappings = IntPtr.Zero;

            int retval = Win32.SHFileOperation(ref FileOpStruct);

            if(retval != 0) return false;
            return true;
        }

        public static bool Move(string source, string dest)
        {
            return Move(new String[] { source }, new String[] { dest });
        }

        public static bool Delete(string file)
        {
            Win32.SHFILEOPSTRUCT FileOpStruct = new Win32.SHFILEOPSTRUCT();

            FileOpStruct.hwnd = IntPtr.Zero;
            FileOpStruct.wFunc = (uint)Win32.FO_DELETE;

            String multiSource = StringArrayToMultiString(new string[] { file });
            FileOpStruct.pFrom = Marshal.StringToHGlobalUni(multiSource);
            FileOpStruct.pTo =  IntPtr.Zero;

            FileOpStruct.fFlags = (ushort)Win32.ShellFileOperationFlags.FOF_SILENT | (ushort)Win32.ShellFileOperationFlags.FOF_NOCONFIRMATION | (ushort)Win32.ShellFileOperationFlags.FOF_NOERRORUI | (ushort)Win32.ShellFileOperationFlags.FOF_NOCONFIRMMKDIR;
            FileOpStruct.lpszProgressTitle = "";
            FileOpStruct.fAnyOperationsAborted = 0;
            FileOpStruct.hNameMappings = IntPtr.Zero;

            int retval = Win32.SHFileOperation(ref FileOpStruct);

            if(retval != 0) return false;
            return true;
        }

        public static bool Move(String[] source, String[] dest)
        {
            Win32.SHFILEOPSTRUCT FileOpStruct = new Win32.SHFILEOPSTRUCT();

            FileOpStruct.hwnd = IntPtr.Zero;
            FileOpStruct.wFunc = (uint)Win32.FO_MOVE;

            String multiSource = StringArrayToMultiString(source);
            String multiDest = StringArrayToMultiString(dest);
            FileOpStruct.pFrom = Marshal.StringToHGlobalUni(multiSource);
            FileOpStruct.pTo = Marshal.StringToHGlobalUni(multiDest);

            FileOpStruct.fFlags = (ushort)Win32.ShellFileOperationFlags.FOF_NOCONFIRMATION;
            FileOpStruct.lpszProgressTitle = "";
            FileOpStruct.fAnyOperationsAborted = 0;
            FileOpStruct.hNameMappings = IntPtr.Zero;

            int retval = Win32.SHFileOperation(ref FileOpStruct);

            if(retval != 0) return false;
            return true;
        }
    }
}