Try this
public ActionResult show(FormCollection form)
{
string firstnamevalue = form["firstname"];
string lastnamevalue = form["lastname"];
List<string> list = new List<string>();
list.Add(firstnamevalue);
list.Add(lastnamevalue);
TempData["Values"] = list;
return RedirectToAction("Redirect");
}
public ActionResult Redirect()
{
//I need to get firstname and lastname here and add to view bag.
List<string> lst=(List<string>)TempData["Values"]// cast tempdata to List of string
ViewBag.Collection=lst;
return View();
}
In view you can access values as
<ul>
<li>First Name: @ViewBag.Collection[0]</li>
<li>Last Name: @ViewBag.Collection[1]</li>
</ul>