CommentController.cs

    public class CommentController  : SitecoreController
    {
        ISitecoreContext _context;
        ISitecoreService _master;
        
        /// <summary>
        /// This constructor can be used with dependency injection or unit testing 
        /// </summary>
        /// <param name="context"></param>
        public CommentController(ISitecoreContext context, ISitecoreService master) 
        {
            _context = context;
            _master = master;
        }

        [HttpGet]
        public override ActionResult Index()
        {

            var model = _context.CreateClass<CommentPage>(false, false, PageContext.Current.Item);
            return View(model);
        }

        [HttpPost]
        public ActionResult Index(Comment comment)
        {
            


            var webModel = _context.CreateClass<CommentPage>(false, false, PageContext.Current.Item);

            if (ModelState.IsValid && comment != null)
            {
                var masterModel = _master.GetItem<CommentPage>(webModel.Id);

                if (masterModel.CommentFolder == null)
                {
                    CommentFolder folder = new CommentFolder();
                    folder.Name = "Comments";

                    using (new SecurityDisabler())
                    {
                        _context.Create(masterModel, folder);
                    }
                    masterModel.CommentFolder = folder;
                }

                using (new SecurityDisabler())
                {
                    comment.Name = DateTime.Now.ToString("yyyyMMddhhmmss");

                    //create the comment in the master database
                    _master.Create(masterModel.CommentFolder, comment);
                    webModel.CommentAdded = true;
                }
            }

           
            return View(webModel);
        }
    }