MVC Bootstrap PopOver with Server-side Validation

Question

I have a simple MVC application that displays a BootStrap PopOver Modal with a form on it. I would like to run some server-side validation against the form as it the data is submitted. If an error is detected, I would like the application to keep the existing form open with the user's data in place while displaying any errors stored in the ModelState.

When I call the "Create" view directly in this application, the form displays errors appropriately. However, when I use the Create view as a modal, it shows the error message stating that there were validation errors, but the ValidationSummary does not display the error details.

How can I get the data from the ModelState back onto the view?

Models/MyViewModel.cs

public class MyViewModel
{
    [Display(Name = "Field #1")]
    public string Field1 { get; set; }

    [Required(ErrorMessage = "Field2 is required.")]
    [StringLength(10)]
    [Display(Name = "Field #2")]
    public string Field2 { get; set; }
}

Controllers/HomeController.cs

public class HomeController : Controller
{
    public ActionResult Index()
    {
        return View();
    }

    public ActionResult Create()
    {
        var data = new MyViewModel {Field1 = "This is field 1!"};
        return PartialView("Create", data);
    }

    [HttpPost]
    public ActionResult Create(MyViewModel model)
    {
        if (!ModelState.IsValid)
        {

            // There were validation errors. Don't lose the data the user entered on the page.
            // Do I need to return the modelstate here?
            return PartialView(model);
        }

        return Json(new { success = true });
    }
}

Views/Home/Index.chstml

@Html.ActionLink("Open the popover modal", "create", null, null, new { id = "modalLink" })
@Html.ActionLink("Navigate directly to the modal page", "Create", "Home")

    <script type="text/javascript">
      $(function () {
        $('#modalLink').click(function () {
          $('#dialog').load(this.href, function () {
            $('#simpleModal').modal('show');
            bindForm(this);
          });
          return false;
        });
      });

      function bindForm(dialog) {
        $('form', dialog).submit(function () {
          $.ajax({
            url: this.action,
            type: this.method,
            data: $(this).serialize(),
            success: function (result) {
              if (result.success) {
                alert('Validation was successful.');
                $('#simpleModal').modal('hide');
              } else {
                // Am I missing something here? 
                alert('Server validation failed!');
              }
            }
          });
          return false;
        });
      }
    </script>

Views/Home/Create.cshtml

@model MvcModalPopupWithValidation.Models.MyViewModel

@using (Html.BeginForm())
{
  <div class="modal fade" id="simpleModal" tabindex="-1" role="dialog" aria-labelledby="simpleModalLabel" aria-hidden="true">
    <div class="modal-dialog">
      <div class="modal-content">
        <div class="modal-header">
          <button type="button" class="close" data-dismiss="modal" aria-hidden="true">&times;</button>
          <h4 class="modal-title" id="simpleModalLabel">
            Modal Validation Test
          </h4>
        </div>
        <div class="modal-body">
          @Html.ValidationSummary(true)

          <div>
            @Html.LabelFor(x => x.Field1)
            @Html.EditorFor(x => x.Field1)
            @Html.ValidationMessageFor(x => x.Field1)
          </div>
          <div>
            @Html.LabelFor(x => x.Field2)
            @Html.EditorFor(x => x.Field2)
            @Html.ValidationMessageFor(x => x.Field2)
          </div>

        </div>
        <div class="modal-footer">
          <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
          <button type="submit" class="btn btn-primary" id="btnDeclineModal">Save changes</button>
        </div>
      </div>
    </div>
  </div>
}

Answer 1

I did manage to get server-side validation to work. I'm still hoping someone might come along with the correct, better, or auto-magic way to accomplish this.

In case anyone is having the same difficulties I was, here are the code changes I had to make to get it to work properly.

Controller Changes

[HttpPost]
public ActionResult Create(MyViewModel model)
{
    if (!ModelState.IsValid)
    {
        var errors = new List<string>();

        foreach (var modelState in ViewData.ModelState.Values)
        {
            errors.AddRange(modelState.Errors.Select(error => error.ErrorMessage));
        }

        return Json(errors);
    }

    return Json(new { success = true });
}

Create.cshtml Changes

  <div id="errorContainer" class="alert alert-danger" style="display: none">
    Validation issues:
    <div id="errors"></div>
  </div>

Index.cshtml Changes

  function bindForm(dialog) {
    $('form', dialog).submit(function () {
      $.ajax({
        url: this.action,
        type: this.method,
        //traditional: true,
        data: $(this).serialize(),
        success: function (result) {
          if (result.success) {
            showValidationErrors(false);
            $('#simpleModal').modal('hide');
            alert('Validation was successful.');
          } else {
            fillErrorList(result);
            showValidationErrors(true);
          }
        }
      });
      return false;
    });

    function showValidationErrors(isShown) {
      if (isShown) {
        $("#errorContainer").show();
      } else {
        $("#errorContainer").hide();
      }
    }

    function fillErrorList(errors) {
      $("#errors").html("");

      var list = document.createElement('ul');

      for (var i = 0; i < errors.length; i++) {
        var item = document.createElement('li');
        item.appendChild(document.createTextNode(errors[i]));
        list.appendChild(item);
      }
      $("#errors").html(list);
    }