gistfile1.cs

    public class NavigationItem : SitecoreItem
    {
    }
    
    [SitecoreType]
    public class NavigationFolder : SitecoreItem
    {
        [SitecoreField("Main Menu")]
        public virtual IEnumerable<NavigationItem> MainMenu { get; set; }
    }
    
    public class SitecoreItem
    {
        public virtual Guid Id { get; set; }
        public virtual string DisplayName { get; set; }
        public virtual string Url { get; set; }
    }
    
    public class NavigationController : Controller
    {
        private readonly ISitecoreContext _sitecoreContext;

        public NavigationController(ISitecoreContext sitecoreContext)
        {
            _sitecoreContext = sitecoreContext;
        }

        public ActionResult MainMenu()
        {
            var topNavigation = _sitecoreContext.GetItem<NavigationFolder>("{1AC8FC92-9B5F-455F-B32C-7B66065808B3}");
            return View(topNavigation.MainMenu);
        }
    }