title: The type or namespace name 'ClaimsIdentity' could not be found
body: <p>I've added these usings and I have the nuget packages installed. Why can I not use Claim? Visual Studio says ClaimsIDentity, Claim and ClaimTypes could not be found.</p>
  
  <p>~/Controllers/AccController.cs</p>
  
  <pre><code>using Microsoft.AspNet.Identity;
  using Microsoft.Owin.Security;
  using System.Threading.Tasks;
  using System.Web;
  using System.Web.Mvc;
  
  namespace MyProject.Controllers
  {
      public class AccController : Controller
      {
          [AllowAnonymous]
          [HttpPost]
          public ActionResult Login(LoginModel model)
          {
              if (!ModelState.IsValid)
              {
                  return View();
              }
  
              // Don't do this in production!
              if (model.Email == "admin@admin.com" &amp;&amp; model.Password == "password")
              {
                  var identity = new ClaimsIdentity(new[] {
                  new Claim(ClaimTypes.Name, "Ben"),
                  new Claim(ClaimTypes.Email, "a@b.com"),
                  new Claim(ClaimTypes.Country, "England")
              },
                      "ApplicationCookie");
  
                  var ctx = Request.GetOwinContext();
                  var authManager = ctx.Authentication;
  
                  authManager.SignIn(identity);
  
                  return Redirect(GetRedirectUrl(model.ReturnUrl));
              }
  
              // user authN failed
              ModelState.AddModelError("", "Invalid email or password");
              return View();
          }
      }
  }
  </code></pre>