ASP.NET MVC Using a Context in a DataController

DataController.cs

    public abstract class DataController : Controller
    {
        private IContext _context;

        #region Constructor

        protected DataController()
        {
            _context = new Context();
        }

        #endregion

        #region Contract

        [ContractInvariantMethod]
        private void ObjectInvariant()
        {
            Contract.Invariant(_context != null);
        }

        #endregion

        #region Properties

        public IContext Context
        {
            get { return _context; }
            protected set { _context = value ?? _context; }
        }

        #endregion

        #region Overrides of Controller

        protected override void Dispose(bool disposing)
        {
            if (disposing)
            {
                Context.Dispose();
            }

            base.Dispose(disposing);
        }

        protected override void OnActionExecuted(ActionExecutedContext filterContext)
        {
            if (filterContext != null && filterContext.Controller != null)
            {
                filterContext.Controller.ViewBag.Context = Context;
            }

            base.OnActionExecuted(filterContext);
        }

        #endregion
    }

MachineController.cs

    public class MachineController : DataController
    {
        [HttpGet]
        public ActionResult Index(int id = 0)
        {
            var machine = id == 0 ? null : Context.Machines.FirstOrDefault(x => x.Id == id);

            return new ContentResult { Content = machine == null ? "No machine :-(" : machine.Name };
        }
    }