TempData not displaying success message Asp.net MVC - asp.net-mvc

Question

I'm using tempdata to give user a "success message" before redirection however at the moment it just redirect without giving the message. Maybe I have it at wrong place, I tried moving it to different parts of the code but it still didn't work.
Index View
#{
ViewBag.Title = "Home Page";
}
#if (TempData["notice"] != null)
{
<p>#TempData["notice"]</p>
}
<div>
<img src="~/Content/Images/TWO_Logo.jpg" alt="Logo" />
</div>
<div class="jumbotron">
<h1></h1>
<p class="lead">
</div>
Home Controller
namespace com.twcl.it.isms.Controllers
{
[Authorize(Roles = "Administrator, Issue, Transaction_Edit, Print")]
public class HomeController : Controller
{
public ActionResult Index()
{
TempData["notice"] = "Your item(s) successfully requested";
ViewBag.SuccessMessage = TempData["SuccesMeassge"];
return View();
}
public ActionResult About()
{
ViewBag.Message = "Your application description page.";
return View();
}
public ActionResult Contact()
{
ViewBag.Message = "Your contact page.";
return View();
}
public ActionResult Logoff()
{
HttpContext.Session.Abandon();
Response.Redirect("http://192.168.5.127");
//Response.StatusCode = 401;
//Response.End();
//////throw new HttpException(401, "Please close your browser to complete Log Off");
return View("Index");
}

Answer 1

In Index Action method just add TempData.Keep("notice"); which will keep tempdata available for next hop.
public ActionResult Index()
{
TempData.Keep("notice");
ViewBag.SuccessMessage = TempData["SuccesMeassge"];
return View();
}
On View to display alert message
#if (TempData.ContainsKey("notice"))
{
<script type="text/javascript">
alert(#TempData["notice"]);
</script>
}
Details about keep and peek.
when-to-use-keep-vs-peek-in-asp-net-mvc

Answer 2

If you are returning a RedirectResponse from your action method, it will send a 302 response back to the browser with the location header set to the url you want to redirect to and the browser makes a new GET request to that url. You will not be able to show an alert before the new GET request.
What you can do is, show the alert message in page rendered by the redirect.
[HttpPost]
public ActionResult Save(SomeViewmodel model)
{
TempData["Msg"] = "Some message";
return RedirectToAction("Index");
}
Now in the view returned by Index action, you can directly access TempData. No need to read and pass it via ViewBag again in Index action.
<script>
var msg = '#TempData["Msg"]';
if (msg.length) {
alert(msg);
}
</script>