How to get selected value from radiobuttonfor in ASP.NET MVC

Question

I have the following simple problem in ASP.NET MVC 4. I have a viewmodel with a list of options (a simple key/value list), and an object which should have the selected value.

I have the following content, where I render the list using a foreach loop and shows the value using RadioButtonFor. But in the post, I don't get any value back.

How do I modify my code, so I can get the id of the selected option in my post?

I have the following form:

@using (Html.BeginForm("Credits","User",FormMethod.Post))
        {

            @Html.EditorFor(model => model.PurchaseAmount)

            <div>


                @foreach (var a in Model.PaymentMethods)
                {
                    <p>
                        @Html.RadioButtonFor(b=>b.PaymentMethods,)
                        @Html.RadioButtonFor(b => b.SelectedPaymentMethod, a.Id)  @a.Name
                    </p>
                }
            </div>


            <div class="form-group">
                <input type="submit" class="btn btn-success" value="@ViewRes.GoToPayment" />
            </div>
        }

I have the following viewmodel:

 public class CreditsViewModel
    {
        public IEnumerable<PaymentMethodViewModel> PaymentMethods { get; set; }
        public PaymentMethodViewModel SelectedPaymentMethod { get; set; }

        public int PurchaseAmount { get; set; }

        public decimal Credit { get; set; }
        public decimal CreditLimit { get; set; }
    }

    public class PaymentMethodViewModel
    {
        public int Id { get; set; }
        public string Name { get; set; }
    }

Post code:

    [HttpPost]
    public ActionResult Credits(CreditsViewModel model)
    {
        string url = "";
        //string returnUrl = orderService.AddFunds(SecurityUtility.CurrentUser.Id, model.Funds);
        return Redirect(url);
    }

Answer 1

//Model.
public class TestRadiobutton
{
    public string Theme { get; set; }
}

  //Controller.
  public class HomeController : Controller
  {
    // GET: Home
    public ActionResult Index()
    {
        TestRadiobutton obj=null;
        if (TempData["MyObj"] != null)
        {
            obj = (TestRadiobutton)TempData["MyObj"];

        }

        return View(obj);
    }
    [HttpPost]
    public ActionResult Change(TestRadiobutton obj)
    {
        TempData["MyObj"] = obj;
        return RedirectToAction("Index");
    }
}


//view.
@model RadioButtonInMvc.Models.TestRadiobutton

 @{
    ViewBag.Title = "Index";
  }

@using (Html.BeginForm("Change", "Home", FormMethod.Post))
{

<div class="jumbotron">
    <div class="row">
        <div class="col-lg-6">
            @Html.RadioButtonFor(m => m.Theme, "Dark")
            <span>Dark Theme</span>
        </div>
        <div class="col-lg-6">
            @Html.RadioButtonFor(m => m.Theme, "Light")
            <span>Light Theme</span>
        </div>
        <div>
            <button type="submit" class="btn btn-primary">Save</button>
        </div>
        <label>@Html.DisplayFor(m => m.Theme)</label>
    </div>
</div>
}

Answer 2

That should be sufficient:

            @foreach (var a in Model.PaymentMethods)
            {
                <p>
                    @Html.RadioButtonFor(b => b.SelectedPaymentMethod, a.Id)  @a.Name
                </p>
            }

Change the SelectedPaymentMethod to be int instead of PaymentMethodViewModel.

Also remove the PaymentMethods from the view model and move it to the ViewBag, this probably breaks the model binding.