Get List of groups and users From LDAP

using System.DirectoryServices;

using System.DirectoryServices.AccountManagement;

using System.DirectoryServices.ActiveDirectory;

public partial class Admin : System.Web.UI.Page

{

    Common common = new Common();

    protected void Page_Load(object sender, EventArgs e)

    {

        if (!Page.IsPostBack)

        {

                //Getting the Current user name

                string username = common.ExtractUserName(User.Identity.Name);

                UserPrincipal user = UserPrincipal.FindByIdentity(new PrincipalContext(ContextType.Domain), IdentityType.SamAccountName, username);

                ArrayList adminGroups = common.GetAdminGroups();//Get the Admin Groups

                ArrayList groups = common.getGroupsByPrincipal(user);//Get the User Groups

                groups.Add(user.DisplayName.ToLower().Trim());

                groups.Add(user.SamAccountName.ToLower().Trim());

                getUsersAndGroup();

                bool redirect = true;

//Check wheather user is admin or not

                if (adminGroups.Count > 0)

                {

                    foreach (string adminGroup in adminGroups)

                    {

                        if (groups.Contains(adminGroup))

                        {

                            redirect = false;

                            break;

                        }

                    }

                    if (redirect)

                    {

                        Response.Redirect("Default.aspx", true);

                    }

                }

        }

    }

    private void getUsersAndGroup()

    {

        try

        {

            ArrayList allUsers = this.getAllUsers();

            ArrayList allGroups = this.getAllGroups();

            DataTable dtGroups = new DataTable();

            dtGroups.Columns.Add("Groups");

            for (int i = 0; i < allGroups.Count; i++)

            {

                DataRow row = dtGroups.NewRow();

                row[0] = allGroups[i];

                dtGroups.Rows.Add(row);

            }

            ddlGroup.DataSource = dtGroups;

            ddlGroup.DataTextField = "Groups";

            ddlGroup.DataValueField = "Groups";

            ddlGroup.DataBind();

        }

        catch (Exception ex)

        {

            ErrorLog.Log(ex);

        }

    }

    public DataTable getUsers(string username)

    {

        DataTable dtUsers = new DataTable();

        dtUsers.Columns.Add("users");

        try

        {

            // create domain context

            PrincipalContext ctx = new PrincipalContext(ContextType.Domain);

            // fetch your group

            GroupPrincipal group = GroupPrincipal.FindByIdentity(ctx, username);

            // enumerate over the group's members

            foreach (Principal p in group.Members)

            {

                DataRow row = dtUsers.NewRow();

                row[0] = p.Name;

                dtUsers.Rows.Add(row);

                //Console.WriteLine("Principal '{0}', type '{1}'", p.Name, p.StructuralObjectClass);

            }

        }

        catch (Exception ex)

        {

            ErrorLog.Log(ex);

        }

        return dtUsers;

    }

    private ArrayList getAllUsers()

    {

        return getADObjectsForClass("User");

    }

    private ArrayList getAllGroups()

    {

        return getADObjectsForClass("Group");

    }

    private ArrayList getADObjectsForClass(string objectClass)

    {

        ArrayList list = new ArrayList();

        try

        {

            DirectoryEntry dirEntry = new DirectoryEntry("LDAP://" + System.Configuration.ConfigurationManager.AppSettings["DomainName"]); //Enter the domain name here

            DirectorySearcher dirSearcher = new DirectorySearcher();

            dirSearcher.SearchRoot = dirEntry;

            dirSearcher.Filter = "(objectClass=" + objectClass + ")";

            dirSearcher.PropertiesToLoad.Add("cn");

            SearchResultCollection res = dirSearcher.FindAll();

            foreach (SearchResult objectUnit in res)

            {

                list.Add(objectUnit.Properties["cn"][0].ToString());

            }

        }

        catch (Exception ex)

        {

            ErrorLog.Log(ex);

        }

        return list;

    }

}