public ActionResult LeapYears(LeapYearSearchTool searchTool)
        {
            if (ModelState.IsValidField("EndYear") && searchTool.StartYear >= searchTool.EndYear)
            {
                ModelState.AddModelError("EndYear", "Please make sure your end date is later than your start date");
            }
            if (ModelState.IsValid)
            {
                var leapFinder = new LeapYearFinder();
                var leapYears  = new LeapYears();

                leapYears.StartYear = searchTool.StartYear.Value;
                leapYears.EndYear   = searchTool.EndYear.Value;

                var result = leapFinder.SearchForLeapYears(leapYears);

                searchTool.Years      = result.Years;
                searchTool.IsPostback = true;
                return(View("LeapYears", searchTool));
            }
            else
            {
                searchTool.Years = new List <int>(); //not sure why this is necessary but I get null ref exception on View without it.

                return(View("LeapYears", searchTool));
            }
        }
        public ActionResult LeapYears()
        {
            var model = new LeapYearSearchTool();

            return(View(model));
        }