title: Post/Redirect/Get - persist when refresh
body: <p>I have main page, consisting of some checkboxes. User has to mark some of them, and then submit. From there, I make some requests to DB and then pull some data, then display it to the user.</p>
  
  <p>I want to use PRG pattern, so after submit if you refresh the page, you won't be asked 'are you sure blabla...'. </p>
  
  <p>Inside my ASP.NET MVC Code I have 2 methods:</p>
  
  <pre><code>public ActionResult RedirectToPreview(DemandLetterModel model)
  </code></pre>
  
  <p>and
      public ActionResult PreviewLetters(DemandLetterModel model)</p>
  
  <p>RedirectToPreview makes requests to DB and gets data back, and then put them on tempdata like this:</p>
  
  <pre><code>TempData["Notices"] = EligibleNotices.GetListOfNotices(notices);
  TempData["Letters"] = letters;
  </code></pre>
  
  <p>In the PreviewLetters, I have:</p>
  
  <pre><code>ViewBag.Notices = TempData["Notices"];
  ViewBag.Letters = TempData["Letters"];
  return View("Preview");
  </code></pre>
  
  <p>It works, but when you refresh the page, it no longer works because of tempdata. How should I do this? I would prefer without session, as it adds complexity.</p>
  
  <p>Might I cache this data only for that refresh? Are there are methods to solve this?</p>