Lectura de datos de usuario de directorio activo a un fichero.

Está también en github aquí

using System;

using System.DirectoryServices;
using System.DirectoryServices.ActiveDirectory;
using System.IO;

namespace udaExe {
    class Program {
        static void Main(string[] args) {
            string ldapEntry;
            string fileName;
            int cantUsuarios = 0;
            if (!GetParameters(args, out ldapEntry, out fileName)) {
                Console.Out.WriteLine("uso: udaExe ldap fichero");
                Console.Out.WriteLine("Ejemplo: udaExe \"LDAP://OU=Users,dc=microsoft,dc=local\" \"c:\\usuarios.txt\"");

            } else {
                Console.Out.WriteLine("Buscando usuarios:");

                using (StreamWriter sw = File.CreateText(fileName)) {
                    try {
                        DirectoryEntry directoryObject = new DirectoryEntry(ldapEntry);
                        foreach (DirectoryEntry child in directoryObject.Children) {
                            string displayName = GetProperty(child, "displayName");
                            string distinguishedName = GetProperty(child, "distinguishedName");
                            string samAccountName = GetProperty(child, "samAccountName");
                            child.Close();
                            child.Dispose();
                            sw.WriteLine($"{displayName}#{samAccountName}#{distinguishedName}");
                            cantUsuarios++;
                        }
                        directoryObject.Close();
                        directoryObject.Dispose();
                    } catch (DirectoryServicesCOMException ex) {
                        Console.Error.WriteLine("Error: " + ex.Message.ToString());
                    }
                }
                Console.Out.WriteLine(cantUsuarios.ToString() + " usuarios encontrados, fichero generado: " + fileName);
            }
        }

        public static string GetProperty(DirectoryEntry de, string PropertyName) {
            if (de.Properties.Contains(PropertyName)) {
                return de.Properties[PropertyName][0].ToString();
            } else {
                return string.Empty;
            }
        }

        public static bool GetParameters(string[] args, out string ldap, out string fileName) {
            ldap = String.Empty;
            fileName = @"c:\users.txt";
            if (args.Length < 1) {
                return false;
            }
            ldap = args[0];
            if (args.Length >= 2) {
                fileName = args[1];
            }
            return true;
        }
    }
}