Creating a new directory from C# with Encrypting File System switched on

Question

Has anyone created a new directory from C# with Encrypting File System switched on?

Additionally any information on doing this from an install would be helpful too.

Answer 1

Creating an encrypted directory would be a two step process - create it using Directory.CreateDirectory and then encrypt it using the Win32 function EncryptFile. Sample code -

using System;
using System.IO;
using System.Runtime.InteropServices;

namespace EncryptDir
{
    public class Sample
    {
        DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        static extern bool EncryptFile(string filename);

        public static void Main ()
        {
            Directory.CreateDirectory("MyEncryptedDirectory");
            EncryptFile("MyEncryptedDirectory");
        }
}

References:
EncryptFile Function @ MSDN
Handling encrypted files and directories @ MSDN

Answer 2

It seems that calling File.EncryptFile also works on directories. I guess it just forwards to EncryptFile internally.

Answer 3

The managed methods File.Encrypt() and FileInfo.Encrypt() both simply call the native EncryptFile() that is shown in the other answer.

So, no need to go to all the trouble to declare the p/invoke API. Just use the built-in methods.