public ActionResult Create(int personId)
{
var person = Repository.OfType<Person>().GetNullableById(personId);
var seminar = SiteService.GetLatestSeminar(Site);
if (person == null || seminar == null) return this.RedirectToAction<ErrorController>(a => a.Index());
var reg = person.GetLatestRegistration(Site);
var invitation = new Invitation(person) {Seminar = seminar, Title= reg != null ? reg.Title : string.Empty, FirmName = reg != null && reg.Firm != null ? reg.Firm.Name : string.Empty};
return View(invitation);
}