MVC 4 model values not passed to controller action - asp.net-mvc-4

Question

I have view and want to display content from the object stored in session one by one when user clicks on NEXT button. View uses WorldModel object to display the data. Id is hidden field and Content should be displayed on page.
View:
#model MvcApplication4.Models.WorldModel
#{
ViewBag.Title = "View1";
Layout = "~/Views/Shared/_Layout.cshtml";
}
<h2>View1</h2>
#using (Html.BeginForm())
{
#Html.AntiForgeryToken()
#Html.ValidationSummary()
<fieldset>
#Html.HiddenFor(model => model.Id)
#Html.DisplayFor(model => model.Content)
<input type="submit" value="Next" />
</fieldset>
}
Model: This class contains two properties id and content. Basically id is mapped to candidate id and Content is mapped to candidate name.
namespace MvcApplication4.Models
{
public class WorldModel
{
public int Id { get; set; }
public string Content { get; set; }
}
}
Controller: Class has two action methods one doesn’t take any parameter and other takes WorldModel as parameter.
namespace MvcApplication4.Controllers
{
public class WorldController : Controller
{
//
// GET: /World/
public ActionResult View1()
{
List<Candidate> obj = new List<Candidate>();
obj.Add(new Candidate() { Id = 1, Name = "ABCD", IsNameDispalyed = false});
obj.Add(new Candidate() { Id = 2, Name = "PQR", IsNameDispalyed = false });
obj.Add(new Candidate() { Id = 3, Name = "XYZ", IsNameDispalyed = false });
CandidateSession cs = new CandidateSession(){Candidates=obj};
Session["Can"] = cs;
return View();
}
[HttpPost]
public ActionResult View1(WorldModel worldModel)
{
CandidateSession cs = (CandidateSession)Session["Can"];
var can1 = cs.Candidates.Where(x => x.IsNameDispalyed == false).First();
can1.IsNameDispalyed = true;
return View(new WorldModel() {Id=can1.Id, Content=can1.Name });
}
}
public class Candidate
{
public int Id { get; set; }
public string Name { get; set; }
public bool IsNameDispalyed { get; set; }
}
public class CandidateSession
{
public List<Candidate> Candidates { get; set; }
}
}
When I access URL as “../World/View1” it fills data to session object and click on NEXT button calls the action public ActionResult View1(WorldModel worldModel). In the method I get the object whose info is not displayed return the view with WorldModel object with id and Content. Now first time the Content is displayed but when the I click on NEXT button it call action public ActionResult View1(WorldModel worldModel). But the id and Content values of worldModel object are null. Why data is null, I set the values in the previous call?