Can't display form input in ASP.NET

Question

I have simple view in ASP.NET 4:

<form action="GetWeather" method="post">
    <input name="city" type="text" />
    <input type="submit" />
</form>
<h1>@ViewBag.City</h1>

And simple controller which was supposed to display input from the form on the same page:

public class WeatherController : Controller
{
    string cityName = "TBD";
    public ActionResult Index()
    {
        ViewBag.City = cityName;
        return View();
    }

    [HttpPost]
    public ActionResult GetWeather(string city)
    {
        cityName = city;
        return Redirect("/Weather/Index");
    }
}

After submit I keep getting my "TBD" string. I couldn't find anything about it, as everything is based on model, which I don't need.

You are not setting ViewBag.City in the action that handles POST. When you debug GetWeather is city correct based on the form input? — Crowcoder
– Crowcoder, Commented Jun 3, 2021 at 14:11
@Crowcoder yes, while debugging, cityName sets to string passed in argument, after redirecting to Index, it is "TBD" again — Erwol
– Erwol, Commented Jun 4, 2021 at 15:20
That is because every request instantiates a new WeatherController and you are setting it to "TBD". I encourage you to pass viewmodels to views instead of relying on viewbag. — Crowcoder
– Crowcoder, Commented Jun 4, 2021 at 15:38

marc_s · Accepted Answer · 2024-02-13 15:55:57Z

1

I would recommend to use strongly typed view instead of using the ViewBag. It would make your code cleaner and easy to maintain.

public class WeatherController : Controller
{
    public ActionResult Index(string city = "TBD")
    {
        return View((object)city);
    }

    [HttpPost]
    public ActionResult GetWeather(string city)
    {            
        return RedirectToAction("Index", new { city });
    }
}

@model string

@using (Html.BeginForm("GetWeather", "Weather", FormMethod.Post))
{
    <input name="city" type="text" />
    <input type="submit" />
}

<h1>@Model</h1>

Why not to use ViewBag heavily?

ViewBag vs Model, in ASP.NET MVC

edited Feb 13, 2024 at 15:55

marc_s

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answered Jun 3, 2021 at 14:49

Victor

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Comments

Omri Attiya · Accepted Answer · 2021-06-04 08:07:10Z

0

try this

[HttpPost]
 public ActionResult GetWeather(string city)
{
    cityName = city;
    return Index();
}

edited Jun 4, 2021 at 8:07

Omri Attiya

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answered Jun 3, 2021 at 14:30

Serge

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