Validation in model not firing - asp.net-mvc

Question

Driving me crazy.... validation not firing.
When I leave the field blank and hit submit it behaves as if the model were valid.
I have used dbFirst entity framework to create the model and added the required data annotation after the fact.
My Model (Entity)
public partial class Certificate
{
public Certificate()
{
this.Travelers = new HashSet<Traveler>();
}
public int ID { get; set; }
public System.DateTime InsertDate { get; set; }
[Required(ErrorMessage = "Please enter your card number.")]
public string CertificateNumber { get; set; }
public Nullable<int> BuyerID { get; set; }
public string Used { get; set; }
public string Active { get; set; }
public virtual ICollection<Traveler> Travelers { get; set; }
}
My Controller:
[HttpPost]
public ActionResult Index(Certificate CertificateNumber)
{
if (ModelState.IsValid)
{
return RedirectToAction("Create", "Travelers");
}
return View();
}
My View:
#model GrandCelebration.Models.Certificate
#{
ViewBag.Title = "Validation";
}
<div>
<h2>Please enter your card number below to validate</h2>
<div id="searchbar">
#using (Html.BeginForm())
{#Html.ValidationSummary(true)
<fieldset>
#Html.TextBoxFor(model => model.CertificateNumber)
<input type="submit" class="btn" alt="Validate" style="display:inline" value="Validate" />
#Html.ValidationMessageFor(model => model.CertificateNumber)
</fieldset>
}
</div>
</div>

Answer 1

The problem was that the required js files weren't included.
Firstly make sure that unobtrusive validation is enabled in Web.config:
<appSettings>
<add key="ClientValidationEnabled" value="true"/>
<add key="UnobtrusiveJavaScriptEnabled" value="true"/>
</appSettings>
Then include 3 js files in the _Layout page:
<script src="http://ajax.microsoft.com/ajax/jQuery/jquery-1.4.2.min.js"></script>
<script src="http://ajax.microsoft.com/ajax/jquery.validate/1.7/jquery.validate.min.js"></script>
<script src="#Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")" type="text/javascript"></script>
When cient-side validation is successfully enabled, if you look at the textbox HTML you will see a data-val property has been added.