using System;
using System.DirectoryServices;
using System.DirectoryServices.AccountManagement;
using System.Linq;

namespace ADSamples
{
    class Program
    {
        static void Main(string[] args)
        {
            GetGroups(x => { Console.WriteLine(x.DistinguishedName); return true; });
#if DEBUG
            Console.Write("Press any key... ");
            Console.ReadKey();
#endif
        }
        public static void GetGroups(Func<GroupPrincipal, bool> func, ContextType contextType = ContextType.Domain, string name = null, string container = null, ContextOptions options = ContextOptions.Negotiate | ContextOptions.Signing | ContextOptions.Sealing, string userName = null, string password = null, int pageSize = 1000, SearchScope searchScope = SearchScope.Subtree)
        {
            using (PrincipalContext context = new PrincipalContext(contextType, name, container, options, userName, password))
            {
                using (GroupPrincipal principal = new GroupPrincipal(context))
                {
                    principal.GroupScope = GroupScope.Global;
                    using (PrincipalSearcher principalSearcher = new PrincipalSearcher(principal))
                    {
                        DirectorySearcher directorySearcher = principalSearcher.GetUnderlyingSearcher() as DirectorySearcher;
                        directorySearcher.PageSize = pageSize;
                        directorySearcher.SearchScope = searchScope;
                        foreach (Principal result in principalSearcher.FindAll())
                        {
                            if (func != null && !func(result as GroupPrincipal))
                                break;
                        }
                    }
                }
            }
        }
    }
}