Using C# to find all CNs in ActiveDirectory

Usage:

To list all computers on the network where Microsoft Active Directory is used.

I faced this problem when I wished to document all computers in the local domain of this company. I found J.O.Donnell's C# solution posted on Auguest 27, 2002. I modified it to make it more flexiable to our case.

Discription:

In Active Directory there is an OU or Organizational Unit. It is actually a folder with a category of computers inside. I assumed that each computer has a LDAP path which is something like LDAP://domain OU=Workstations CN=localhost. In my design I will read all CNs in a specific domain with or without given OU.

The C# solution is straight forward. I always like a simple answer.

Execution:

C:> ListCN.exe domain contains notContains

E.g. Use the command bellow to find out all non-obsoleted Workstations and Servers in the domain of MFCHINA:

C:> ListCN.exe MFCHINA Workstations;Servers Obsoleted

//ListCN
//Displays all computer names in an Active Directory
//Written 08/26/02 - John O'Donnell - csharpconsulting@hotmail.com
//Modified 06/14/10 - River Liu - output all workstations in certain LDAP 

using System;
using System.DirectoryServices;
using Microsoft.Office.Core;
using Microsoft.CSharp;
using Excel = Microsoft.Office.Interop.Excel;
using System.Collections.Generic;
using System.Text;


namespace ActiveDirectorySearch1
{
    class Class1
    {
        static void Main (string[] args)
        {
            String domain="";
            String contain="";
            String notContain="";

            if (args.Length <= 0)
                Environment.Exit(-1);

            else
            {
                domain = args[0];
            }

            if (args.Length >= 2)
            {
                contain = args[1];
            }

            if (args.Length >= 3)
            {
                notContain = args[2];
            }

            String ldap = "LDAP://" + domain;
            String[] contains = contain.Split(';');
            String[] notContains = notContain.Split(';');

            DirectoryEntry entry = new DirectoryEntry(ldap);
            DirectorySearcher mySearcher = new DirectorySearcher(entry);
            mySearcher.Filter = ("(objectClass=computer)");
            Console.WriteLine("Listing of computers in the Active Directory");  
            Console.WriteLine("============================================");



foreach(SearchResult resEnt in mySearcher.FindAll())
           {                
                String path = resEnt.GetDirectoryEntry().Path.ToString();
                String cn;
                Boolean contained = true;
                Boolean containedNot = false;

                foreach (string con in contains)
                {
                    if (String.Compare(con, "") == 0);
                    else
                        contained &= path.Contains(con);
                }

                foreach (string notCon in notContains)
                {
                    if (String.Compare(notCon, "") == 0);
                    else
                        containedNot |= path.Contains(notCon);
                }

                if (contained == true && containedNot == false)
                {
                    cn = resEnt.GetDirectoryEntry().Name.ToString();
                    cn = cn.Substring(3);
                    Console.WriteLine(cn);
                    using (System.IO.StreamWriter file = new System.IO.StreamWriter(@"CNlist.inf", true))
                    {
                        file.WriteLine(cn);
                        //file.WriteLine(cn + "," + path);
                    }
                }  
            }
            
            Console.WriteLine("===========    End of Listing   =============");       
        }
    }

}