see all nodes in given ldap node, C#

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//my ldap utilities

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Collections;
using System.DirectoryServices;
using System.IO;

namespace Ldap
{
    class LdapStructure
    {
        static void Main(string[] args)
        {
            int depth;
            if (args.Length < 2 || string.IsNullOrEmpty(args[0]) || !Int32.TryParse(args[1], out depth) || depth < 0)
            {
                Console.WriteLine("\nUsage: <.exe> ldap_node (without LDAP://, but wrapped IN QUOTES!!!) depth [output_file]");
                return;
            }
            if (args.Length >= 3)
                using (TextWriter tw = new StreamWriter(args[2]))
                {
                    EnumerateOU(args[0], depth, tw);     
                }
            else
                EnumerateOU(args[0], depth, Console.Out);            
        }

public static void EnumerateOU(string OuDn, int depth, TextWriter tw)
        {
            try
            {
                tw.WriteLine();
                using (DirectoryEntry directoryObject = new DirectoryEntry("LDAP://" + OuDn))
                {
                    foreach (DirectoryEntry child in directoryObject.Children)
                        ShowChildren(child, "", depth, tw);
                }
            }
            catch (Exception e)
            {
                tw.WriteLine("\nAn Error Occurred: " + e.Message.ToString());
            }
        }

public static void ShowChildren(DirectoryEntry parent, string print_prefix, int depth, TextWriter tw)
        {
            if (depth == 0)
                return;
            try
            {
                tw.WriteLine("{0} ({1})", print_prefix + parent.Path.ToString().Remove(0, 7), parent.Name);
                if (depth == 1)
                    return;
                foreach (DirectoryEntry child in parent.Children)
                    ShowChildren(child, print_prefix + "\t", depth - 1, tw);
            }
            catch (Exception e)
            {
                tw.WriteLine(e.Message);
            }
            finally
            {
                parent.Close();
                parent.Dispose();
            }
        }
    }
}

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Compilation time: 1.25 s