ASP.NET MVC: Active Directory Integration

Implementation:

using System.DirectoryServices.AccountManagement;
using System.Linq;
using System.Web;
using System.Configuration;

public class CurrentUser
{
    public static UserPrincipal User
    {
        get 
        { 
            return UserPrincipal.FindByIdentity(new PrincipalContext(ContextType.Domain), Username);
        }
    }

    public static PrincipalSearchResult Groups
    {
        get
        {
            return User.GetAuthorizationGroups();
        }
    }

    public static string Username
    {
        get { return HttpContext.Current.User.Identity.Name.Split('\\')[1]; }
    }
}

Helper Class:

using System.Collections.Generic;
using System.DirectoryServices.AccountManagement;
using System.Linq;

public static class ActiveDirectory
{
    public static IEnumerable GetGroups(string name)
    {
        var context = new PrincipalContext(ContextType.Domain);
        var group = new GroupPrincipal(context) { Name = "*" + name + "*", IsSecurityGroup = true};
        var searcher = new PrincipalSearcher(group);
        var results = searcher.FindAll();
        return results.OrderBy(x => x.Name).Cast().ToList();
    }

    public static IEnumerable GetUsers(string name)
    {
        var context = new PrincipalContext(ContextType.Domain);
        var user = new UserPrincipal(context) { DisplayName = "*" + name + "*", Enabled = true };
        var searcher = new PrincipalSearcher(user);
        var results = searcher.FindAll();
        return results.OrderBy(x => x.DisplayName).Cast().ToList();
    }

    public static IEnumerable GetUsersByGroup(string name)
    {
        return GetGroup(name).Members.Cast().ToList();
    }

    public static UserPrincipal GetUser(string username)
    {
        return UserPrincipal.FindByIdentity(new PrincipalContext(ContextType.Domain), username);
    }

    public static GroupPrincipal GetGroup(string name)
    {
        return GroupPrincipal.FindByIdentity(new PrincipalContext(ContextType.Domain), name);
    }

    public static UserPrincipal GetUserByGuid(string guid)
    {
        return UserPrincipal.FindByIdentity(new PrincipalContext(ContextType.Domain), IdentityType.Guid, guid.ToGuid().ToString());
    }

    public static UserPrincipal GetUserByDisplayName(string displayName)
    {
        var context = new PrincipalContext(ContextType.Domain);
        var user = new UserPrincipal(context) { DisplayName = displayName, Enabled = true };
        var searcher = new PrincipalSearcher(user);
        return (UserPrincipal) searcher.FindOne();
    }
}