Question

I have a ViewModel with a property as below:

    [DisplayName("As Configured On:")]
    [DisplayFormat(DataFormatString="{0:d}", ApplyFormatInEditMode=true)]
    public DateTime ConfigDate { get; set; }

The Form that displays the ConfigDate is as below:

<%= Html.EditorFor(Model => Model.ConfigDate)%>

When the Index Action comes back, everything looks formatted correctly, i.e. the <input> box has the date value as 12/12/2001. When the form is posted, the result that comes back is as though the DisplayFormat attribute isn’t being applied.

EDIT:
More info was requested: here is the code en toto:

The Search Form

<%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<Config.Web.Models.AirplanesViewModel>" %>
<% using (Html.BeginForm("Details", "Airplanes", FormMethod.Post, new { id = "SearchForm" })) { %>
<%= Html.LabelFor(model => model.ConfigDate) %>
<%= Html.EditorFor(Model => Model.ConfigDate)%>
<input id="searchButton" type="submit" value="Search" />
<% } %>

The AirplanesViewModel

    public class AirplanesViewModel
{
    [DisplayName("As Configured On:")]
    [DisplayFormat(DataFormatString="{0:d}", ApplyFormatInEditMode=true)]
    public DateTime ConfigDate { get; set; }
}
}

The Controller

        [HttpGet]
    public ActionResult Index()
    {
        AirplanesViewModel avm = new AirplanesViewModel
        {
            ConfigDate = DateTime.Now
        };
        return View(avm);
    }


    [HttpPost]
    [ActionName("Details")]
    public ActionResult Details_Post(AirplanesViewModel avm)
    {
        return RedirectToAction("Details", avm);
    }


    [HttpGet]
    public ActionResult Details(AirplanesViewModel avm)
    {
        int page = 0;
        int pageSize = 10;

        if (!ModelState.IsValid)
        {
            avm.Airplanes = new PaginatedList<Airplane>();
            return View(avm);
        }

        try
        {
            Query q = new Query(avm.Query);

            PaginatedList<Airplane> paginatedPlanes = new PaginatedList<Airplane>(repo.ByQuery(q), page, pageSize);

            avm.Airplanes = paginatedPlanes;

            return View(avm);
        }
        catch (Exception)
        {
            // Should log exception
            avm.Airplanes = new PaginatedList<Airplane>();
            return View(avm);
        }
    }

Additional Information

It has something to do with the redirection to the GET Action. When I take out the POST Action and remove the GET attribute (so both GET and POST use the Details() Action) the problem goes away – but this also gets rid of my pretty URL’s when the form is submitted (and causes the annoying “are you sure?” popup on refresh). Strangely, the only problem is the loss of formatting in that field. Everything else is fine.

Answer 1

While waiting for you to clearly specify the problem, here’s a full working counter example that what you describe in your question doesn’t actually happen:

Model:

public class MyViewModel
{
    [DisplayName("As Configured On:")]
    [DisplayFormat(DataFormatString = "{0:d}", ApplyFormatInEditMode = true)]
    public DateTime ConfigDate { get; set; }
}

Controller:

public class HomeController : Controller
{
    public ActionResult Index()
    {
        var model = new MyViewModel
        {
            ConfigDate = DateTime.Now
        };
        return View(model);
    }

    [HttpPost]
    public ActionResult Index(MyViewModel model)
    {
        return View(model);
    }
}

View:

<% using (Html.BeginForm()) { %>
    <%= Html.EditorFor(x => x.ConfigDate) %>
    <input type="submit" value="OK" />
<% } %>

You can submit the form as much as you wish, the formatting will be preserved.

---

UPDATE:

After providing additional information here’s why the problem occurs. When you redirect to the Details action with return RedirectToAction("Details", avm); a query string parameter is applied to the url:

http://localhost:1114/Airplanes/Details?ConfigDate=11/30/2010%2000:00:00

Notice how the hour is included and that’s normal. Now when you return the view in the Details GET action the HTML helper responsible for generating the editor template will do the following tasks:

Check to see whether there’s a ConfigDate parameter (either GET or POST). If none was found check the value of the Model which is passed to the view and use the ConfigValue property of the model and generate the textbox.

As a ConfigValue is found in the query string the model is not used at all. So it simply takes the value passed in the redirect which also contains the time and uses it to bind to it.