Полный код HelloWorldFS

using System;
using System.Collections.Generic;
using System.IO;
using System.Security.AccessControl;
using System.Text;
using DokanNet;

namespace XakepFS
{
    class HelloWorldFSClass : IDokanOperations
    {
        public void Cleanup(string fileName, DokanFileInfo info)
        {
        }

        public void CloseFile(string fileName, DokanFileInfo info)
        {
        }

        public NtStatus CreateFile(string fileName, DokanNet.FileAccess access, FileShare share, FileMode mode, FileOptions options, FileAttributes attributes, DokanFileInfo info)
        {
            return NtStatus.Success;
        }

        public NtStatus DeleteDirectory(string fileName, DokanFileInfo info)
        {
            return NtStatus.Success;
        }

        public NtStatus DeleteFile(string fileName, DokanFileInfo info)
        {
            return NtStatus.Success;
        }

        public NtStatus FindFiles(string fileName, out IList<FileInformation> files, DokanFileInfo info)
        {
            files = new List<FileInformation>();
            FileInformation fi;
            GetFileInformation("\\HelloWorld.txt", out fi, null);
            files.Add(fi);
            return NtStatus.Success;
        }

        public NtStatus FindFilesWithPattern(string fileName, string searchPattern, out IList<FileInformation> files, DokanFileInfo info)
        {
            return FindFiles(null, out files, null);
        }

        public NtStatus FindStreams(string fileName, out IList<FileInformation> streams, DokanFileInfo info)
        {
            throw new NotImplementedException();
        }

        public NtStatus FlushFileBuffers(string fileName, DokanFileInfo info)
        {
            return NtStatus.Success;
        }

        public NtStatus GetDiskFreeSpace(out long freeBytesAvailable, out long totalNumberOfBytes, out long totalNumberOfFreeBytes, DokanFileInfo info)
        {
            freeBytesAvailable = 0x4000000;
            totalNumberOfBytes = 0x4000000 * 5;
            totalNumberOfFreeBytes = 0x4000000;
            return NtStatus.Success;
        }

        public NtStatus GetFileInformation(string fileName, out FileInformation fileInfo, DokanFileInfo info)
        {
            if (fileName == "\\") //Возвращаем корректную информацию о корневой папке
            {
                fileInfo = new FileInformation
                {
                    FileName = "\\",
                    LastAccessTime = DateTime.Now,
                    Attributes = FileAttributes.Directory
                };
                return NtStatus.Success;
            }
            if (fileName != "\\HelloWorld.txt")
            {
                fileInfo = new FileInformation { };
                return NtStatus.NoSuchFile;
            }
            fileInfo = new FileInformation
            {
                Attributes = FileAttributes.Normal,
                CreationTime = DateTime.Now,
                FileName = "HelloWorld.txt",
                LastAccessTime = DateTime.Now,
                LastWriteTime = DateTime.Now,
                Length = 57 //Длина в байтах строки, которую мы возвращаем через ReadFile
            };
            return NtStatus.Success;
        }

        public NtStatus GetFileSecurity(string fileName, out FileSystemSecurity security, AccessControlSections sections, DokanFileInfo info)
        {
            security = null;
            return NtStatus.Error;
        }

        public NtStatus GetVolumeInformation(out string volumeLabel, out FileSystemFeatures features, out string fileSystemName, out uint maximumComponentLength, DokanFileInfo info)
        {
            volumeLabel = "Hello world!";
            features = FileSystemFeatures.None;
            fileSystemName = "HelloWorldFS";
            maximumComponentLength = 256;
            return NtStatus.Success;
        }

        public NtStatus LockFile(string fileName, long offset, long length, DokanFileInfo info)
        {
            throw new NotImplementedException();
        }

        public NtStatus Mounted(DokanFileInfo info)
        {
            return NtStatus.Success;
        }

        public NtStatus MoveFile(string oldName, string newName, bool replace, DokanFileInfo info)
        {
            throw new NotImplementedException();
        }

        public NtStatus ReadFile(string fileName, byte[] buffer, out int bytesRead, long offset, DokanFileInfo info)
        {
            bytesRead = 0;
            var x = Encoding.ASCII.GetBytes("Hello World from HelloWorldFS!\r\nThis is just a test file.");
            if (info.Context == null) // memory mapped read
            {
                using (var stream = new MemoryStream(x))
                {
                    stream.Position = offset;
                    bytesRead = stream.Read(buffer, 0, buffer.Length);
                }
            }
            return NtStatus.Success;
        }

        public NtStatus SetAllocationSize(string fileName, long length, DokanFileInfo info)
        {
            throw new NotImplementedException();
        }

        public NtStatus SetEndOfFile(string fileName, long length, DokanFileInfo info)
        {
            throw new NotImplementedException();
        }

        public NtStatus SetFileAttributes(string fileName, FileAttributes attributes, DokanFileInfo info)
        {
            throw new NotImplementedException();
        }

        public NtStatus SetFileSecurity(string fileName, FileSystemSecurity security, AccessControlSections sections, DokanFileInfo info)
        {
            throw new NotImplementedException();
        }

        public NtStatus SetFileTime(string fileName, DateTime? creationTime, DateTime? lastAccessTime, DateTime? lastWriteTime, DokanFileInfo info)
        {
            throw new NotImplementedException();
        }

        public NtStatus UnlockFile(string fileName, long offset, long length, DokanFileInfo info)
        {
            throw new NotImplementedException();
        }

        public NtStatus Unmounted(DokanFileInfo info)
        {
            return NtStatus.Success;
        }

        public NtStatus WriteFile(string fileName, byte[] buffer, out int bytesWritten, long offset, DokanFileInfo info)
        {
            throw new NotImplementedException();
        }
    }
}