MVC 4 @HTML.HiddenFor are not updating on a postba

Question

This question already has an answer here:

• Hiddenfor not getting correct value from view model 3 answers

Having issues with the view state on a series of page views -- On the initial view of a page in Razor I am using Html.HiddenFor as follows:

    @Html.HiddenFor(x => Model.err)
    @Html.HiddenFor(x => Model.errField)
    @Html.HiddenFor(x => Model.errMessage)
    @Html.HiddenFor(x => Model.IsMove)

which seems to work fine. My hidden input tags contain the correct values. However when I submit the form [HTTPPost] and update the model in my controller action with..

       model.err = transHelper.err;
       model.errField = transHelper.errField;
       model.errMessage = transHelper.errMessage;
       return View(model);

The hidden fields do not seem to update, they contain the original values from the initial view. However When I use these fields in another context within the same razor view like this...

     @*      
        this seems to not update correctly...

    @Html.HiddenFor(x => Model.err)
    @Html.HiddenFor(x => Model.errField)
    @Html.HiddenFor(x => Model.errMessage)
    @Html.HiddenFor(x => Model.IsMove)

        *@
        <input type="hidden" id="err" value="@Model.err" />
        <input type="hidden" id="errField" value="@Model.errField" />
        <input type="hidden" id="errMessage" value="@Model.errMessage" />
        <input type="hidden" id="IsMove" value="@Model.IsMove" />

    </div>

Then the input fields update correctly. I even created a View Helper to help debug, and in all cases, the Model seems to have correct data in HtmlHelper<TModel> -- I even returned the Model as return Json(model); and the data was fine.

At this point I am running with the work around, but does anybody know why @Html.HiddenFor is dirty.

Update: here is my controller actions

  [HttpPost]
   public ActionResult Index(HomePageModel model)
   {


       // process transaction
       Transactionr transr = new Transactionr();
       transr.Process(model);

       model.err = transr.err;
       model.errField = transr.errField;
       model.errMessage = transr.errMessage;

       return View(model);
   }

Here is my view:

        @model App.Models.HomePageModel
    @{
        ViewBag.Title = "Product Categorizer";
    }
    <form id="formData" method="post" action="/Home/Index">
        @Html.AntiForgeryToken()
        <fieldset>
            <div>

            @Html.HiddenFor(model => model.err)
            @Html.HiddenFor(model => model.errField)
            @Html.HiddenFor(model => model.errMessage)
            @Html.HiddenFor(model => model.IsMove)

            <input type="hidden" id="myerr" value="@Model.err" />
            <input type="hidden" id="myerrField" value="@Model.errField" />

            </div>

           <div class="section group">
                <div class="col span_2_of_2">
                     <div class="message" id ="message">
                         @if (Model.err < 0)
                         {
                             <span style="color: purple;">@Model.errMessage (@Model.err) - (@Model.errField)</span>
                         }
                         else if (Model.err > 0)
                         {
                             <span style="color:red;">@Model.errMessage (@Model.err) (@Model.errField)</span>
                         } else {
                            <span>@Model.errMessage (@Model.err) (@Model.errField)</span>
                         }
                         </div>
                     </div>
            </div>

            <div class="section group" id="workspace">
                  @Html.Partial("_WorkspacePartial", Model)
            </div>
              <div class="section group" id="details">
                  @Html.Partial("_DetailPartial", Model)
              </div>


        </fieldset>
        </form>

Here is my model:

 public class HomePageModel
 {
    public int FromStore { get; set; }

    //  the "To" part of the copy/move transaction
    public int ToStore { get; set; }

    // a list of the copy/move transaction
    public List<int> Details { get; set; }


    // true is move false is copy
    public bool IsMove { get; set; }

    // current message
    public int err { get; set; }
    public int errField { get; set; }
    public string errMessage { get; set; }

Answer 1

I think you should be using them like this instead:

@Html.HiddenFor(x => x.Err)
@Html.HiddenFor(x => x.ErrField)
@Html.HiddenFor(x => x.ErrMessage)
@Html.HiddenFor(x => x.IsMove)

Without seeing your model, I am assuming it looks something like this:

public class ErroViewModel
{
  public string Err { get; set; }
  public string ErrField { get; set; }
  public string ErrMessage { get; set; }
  public bool IsMove { get; set; }
}

If not it should be similar with public properties as above.

Update

In your get do you have the following?

public ActionResult Index(HomePageModel model)
{
   var model = new HomePageModel();
   return View(model);
}

I would also change your form from this:

 <form id="formData" method="post" action="/Home/Index">

To this:

@using (Html.BeginForm("Index", "Home", FormMethod.Post))
{
  // rest of form
}