File Stream C#

using System;
using System.IO;
using System.Security.AccessControl;
    class DirectoryExample
    {
        public static void Main()
        {
            string DirectoryName = "TestDirectory";
            AddDirectorySecurity(DirectoryName, @"MYDOMAIN\MyAccount", FileSystemRights.ReadData, AccessControlType.Allow);
            RemoveDirectorySecurity(DirectoryName, @"MYDOMAIN\MyAccount", FileSystemRights.ReadData, AccessControlType.Allow);
        }
        public static void AddDirectorySecurity(string FileName, string Account, FileSystemRights Rights, AccessControlType ControlType)
        {
            DirectoryInfo dInfo = new DirectoryInfo(FileName);
            DirectorySecurity dSecurity = dInfo.GetAccessControl();
            dSecurity.AddAccessRule(new FileSystemAccessRule(Account,Rights,ControlType));
            dInfo.SetAccessControl(dSecurity);
        }
        public static void RemoveDirectorySecurity(string FileName, string Account, FileSystemRights Rights, AccessControlType ControlType)
        {
            DirectoryInfo dInfo = new DirectoryInfo(FileName);
            DirectorySecurity dSecurity = dInfo.GetAccessControl();
            dSecurity.RemoveAccessRule(new FileSystemAccessRule(Account,Rights,ControlType));
            dInfo.SetAccessControl(dSecurity);
        }
    }