VendorsController.cs

public class VendorsController : Controller
{
    private readonly IRepository _repository;
    private readonly IMappingRegistry _mappingRegistry;
    public VendorsController(IRepository repository, IMappingRegistry mappingRegistry)
    {
        _repository = repository;
        _mappingRegistry = mappingRegistry;
    }

    public ActionResult Details(int vendorId)
    {
        var vendor = _repository.Get<Vendor>(vendorId);
        if(vendor == null)
        {
            return RedirectToAction("Search");
        }

        var viewModel = _mappingRegistry.Map<Vendor, VendorDetailsModel>(vendor);
        return View(viewModel);
    }

    public ActionResult Search()
    {
        // some search implementation
        return View();
    }
}