Question

I have the following actions in my home controller. when i post to the GetDistance() it never goes to the /Home/ShowDistance page but stays on the /Home/Index page. I have checked that the lat and lon values are not null so the browser should be redirected to /Home/ShowDistance.

public ActionResult Index()
{
    return View();
}

[HttpPost]
public ActionResult GetDistance(string lat, string lon)
{
    if (lat != null && lon != null)
    {
        Session["latlon"] = new LatLon { Latitude = double.Parse(lat), Longitude = double.Parse(lon) };
        return RedirectToAction("ShowDistance");
    }
    return RedirectToAction("Index");    
}

public ActionResult ShowDistance()
{
    //...
    return View();
}

Answer 1

In your Index.cshtml view make sure that you specify the correct controller action to post to (because it has a different name than the one used to render the form). So instead of:

@using (Html.BeginForm())
{
    ...
} 

use:

@using (Html.BeginForm("GetDistance", null))
{
    ...
} 

---

Or if you don’t use a standard HTML <form> to invoke the GetDistance action but an AJAX call, then it’s perfectly normal that the browser url stays at /Home/Index. The whole point of AJAX is to perform an asynchronous HTTP request to the server without navigating away from the current page (which in your case is /Home/Index). If this is the case and you want to redirect you will have to do it on the client in the success callback:

$.ajax({
    url: '@Url.Action("GetDistance")',
    type: 'POST', 
    data: { lat: '123', lon: '456' },
    success: function(result) {
        window.location.href = result.redirectTo;
    }
});

You will also have to modify your GetDistance POST action so that instead of redirecting it returns a JSON object containing the target url to redirect to that can be used in the success callback:

[HttpPost]
public ActionResult GetDistance(string lat, string lon)
{
    if (lat != null && lon != null)
    {
        Session["latlon"] = new LatLon { Latitude = double.Parse(lat), Longitude = double.Parse(lon) };
        return Json(new { redirectTo = Url.Action("ShowDistance") });
    }
    return Json(new { redirectTo = Url.Action("Index") });
}

Obviously this kind of defeats the purpose of AJAX a little because as I said the whole point of AJAX is to perform asynchronous requests to the server and stay on the same page. So in this case you should probably stick with a standard HTML <form>.