an asp.net-mvc Model Binder that respects the ISO 8601 standard. look it up, yo!

Iso8601DateTimeBinder.cs

using System;
using System.Globalization;
using System.Web.Mvc;

namespace Zomg.Web.ModelBinders
{
  public class Iso8601DateTimeBinder : DefaultModelBinder
  {
    public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
    {
      var name = bindingContext.ModelName;
      var value = bindingContext.ValueProvider.GetValue(name);
      if (value == null) return null;

      return parseIso8601Date(value) ?? base.BindModel(controllerContext, bindingContext);
    }

    private DateTime? parseIso8601Date(ValueProviderResult value)
    {
      DateTime date;
      return DateTime.TryParseExact(value.AttemptedValue, "o", null, DateTimeStyles.RoundtripKind, out date) ? date : null as DateTime? ;
    }
  }
}

Iso8601DateTimeBinderSpecs.cs

using System;
using System.Collections.Specialized;
using System.Web.Mvc;
using Zomg.Specs.Infrastructure;
using Zomg.Web.ModelBinders;

namespace Specs_for_Iso8601DateTimeBinder
{
  public class when_binding_to_an_iso_8601_datetime_string : Concerns
  {
    private DateTime _realDate;
    private DateTime? _boundDate;

    protected override void Context()
    {
      _realDate = new DateTime(1981, 04, 28, 15, 32, 51, 147, DateTimeKind.Utc);
      var fields = new NameValueCollection { { "somedate", "1981-04-28T15:32:51.1470000Z" } };
      var metaCrap = ModelMetadataProviders.Current.GetMetadataForType(null, typeof(DateTime?));

      var binderContext = new ModelBindingContext
      {
        ModelName = "somedate",
        ModelMetadata = metaCrap,
        ValueProvider = new NameValueCollectionValueProvider(fields, null)
      };

      _boundDate = new Iso8601DateTimeBinder().BindModel(new ControllerContext(), binderContext) as DateTime?;
    }

    [Specification]
    public void bind_it()
    {
      _boundDate.ShouldEqual(_realDate).And().Value.Kind.ShouldEqual(DateTimeKind.Utc);
    }
  }

  public class when_binding_to_a_non_iso_8601_datetime_string : Concerns
  {
    private DateTime _realDate;
    private DateTime? _boundDate;

    protected override void Context()
    {
      _realDate = new DateTime(1981, 04, 28, 15, 32, 51, 147, DateTimeKind.Utc);
      var fields = new NameValueCollection { { "somedate", "1981-04-28T15:32:51.147" } };
      var metaCrap = ModelMetadataProviders.Current.GetMetadataForType(null, typeof(DateTime?));

      var binderContext = new ModelBindingContext
      {
        ModelName = "somedate",
        ModelMetadata = metaCrap,
        ValueProvider = new NameValueCollectionValueProvider(fields, null)
      };

      _boundDate = new Iso8601DateTimeBinder().BindModel(new ControllerContext(), binderContext) as DateTime?;
    }

    [Specification]
    public void fall_back_to_default_datetime_binding()
    {
      _boundDate.ShouldEqual(_realDate).And().Value.Kind.ShouldEqual(DateTimeKind.Unspecified);
    }
  }

  public class when_binding_to_a_non_datetime_string : Concerns
  {
    private DateTime? _boundDate;

    protected override void Context()
    {
      var fields = new NameValueCollection { { "somedate", "ZOMG:123" } };
      var metaCrap = ModelMetadataProviders.Current.GetMetadataForType(null, typeof(DateTime?));

      var binderContext = new ModelBindingContext
      {
        ModelName = "somedate",
        ModelMetadata = metaCrap,
        ValueProvider = new NameValueCollectionValueProvider(fields, null)
      };

      _boundDate = new Iso8601DateTimeBinder().BindModel(new ControllerContext(), binderContext) as DateTime?;
    }

    [Specification]
    public void fall_back_to_default_datetime_binding()
    {
      _boundDate.ShouldBeNull();
    }
  }
}