It’s been a while since I’ve posted and I’m trying to get back into the swing of things again. I don’t really have a lot to say about the problem, just yet. We’ve identified some breaking changes with ASP.Net MVC 2.0 RC 2.

RC 2 switches to relying on all data annotations on the model when doing validation, when previous releases only checked the values posted and properly bound to a model. To be honest, initially, I didn’t like that idea. It was confusion to me why my model was attributed with attributes requiring fields, but validation was not happening as I expected.

Over time, I came to appreciate, and apparently exploit this feature to do conditional validation. Since the form only posts the enabled controls, I was able to simply enable/disable inputs and doing so, enable/disable their required attribute for model validation.

Everything worked great, until things changed in RC2.

You can read more about the decision to make the switch.

Apparently I’m not the only one to have this sneaky little problem that has been driving me mad. Given the simple model:

public class Foo {
    [Required] public string Bar {get;set;}
}

And a simple view:

<%@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/Site.Master"
Inherits="System.Web.Mvc.ViewPage<Foo>" %>
<%@ Import Namespace="MvcApplication2.Models"%>

<asp:Content ID="Content1" ContentPlaceHolderID="TitleContent" runat="server">
	Index
</asp:Content>

<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">

<script src="/Scripts/jquery-1.3.2.js" type="text/javascript"></script>
<script src="/Scripts/jquery.validate.js" type="text/javascript"></script>
<script src="/Scripts/MicrosoftMvcJQueryValidation.js" type="text/javascript"></script>

 <h2>Index</h2>
 <%= Html.ValidationSummary() %>
 <% Html.EnableClientValidation(); %>
 <%
  using (Html.BeginForm())
  {
    ViewContext.FormContext.ClientValidationFunction = "EnableClientValidation"; %>
    <%= Html.LabelFor(x=>x.Bar) %>
    <%= Html.TextBoxFor(x=>x.Bar) %>
    <input type="submit" />
<%  } %>
</asp:Content>

You would expect the form to emit the JSON needed to pass to the jQuery validator right? WRONG! It just outputs the following

<script type="text/javascript">
//<![CDATA[
EnableClientValidation({"Fields":[],"FormId":"form0"}, null);
//]]>
</script>

That’s no help; however, when you give it the <%= Html.ValidationMessageFor(x=>x.Bar) %> you start to see what you expect.

While figuring out the ASP.Net MVC 2.0 Preview 2 Expression HtmlHelpers (that’s a mouthful), I ran into this error a couple times. It didn’t make any sense to me because there shouldn’t be ViewData item with the key “MyProperty” with that type.

It turns out I was doing this:

<%= Html.DropDownListFor(x=>x.MyProperty, Model.AllMyPropertyListItems) %>

It throws this exception when AllMyPropertyListItems is null.

As a follow up to my previous post, testing when ModelState is relatively simple, but leaves me feelings a little uneasy about my tests.

Here is an example tests, stripped down to remove some of the unnecessary bits

public class When_submitting_lead_data_that_is_in_an_invalid_state : Specification
{
    // class fields...etc

    protected override void Given()
    {
        base.Given();
        _mockOrdersRepository = MockRepository.GenerateStub<IOrdersRepository>();
        _checkoutController = new CheckoutController(_mockOrdersRepository);

        _leadDataWithEmptyPlanName = new PreCheckoutViewData();

        // add an error to the model state
        _checkoutController.ModelState.AddModelError("", "");

        _exceptionWasThrown = false;
    }

    protected override void When()
    {
        base.When();
        try
        {
            _checkoutController.Checkout(_leadDataWithEmptyPlanName);
        } catch(ArgumentNullException)
        {
            _exceptionWasThrown = true;
        }
    }

    [Then] public void an_exception_is_thrown()
    {
        _exceptionWasThrown.ShouldBe(true);
    }
}

This feels pretty loose to me, but there can be another tests that tests which states the model will appear invalid.