Remote validation attribute in MVC3 invalid get format

Question

I trying to use remote validation for the first time, but am encountering problems with the parameters passed inot the remote validation method.

My model is as follows:

public class PerinatalWomanView : IPerinatalWoman
{
[Required(ErrorMessage = "The woman's postcode is required")]
    [Display(Name = "Woman's postcode")]
    [Remote("PostcodeCheck", "Validation", "Validation")]
    [RegularExpression("^[a-zA-Z]{1,2}[0-9][0-9A-Za-z]{0,1} [0-9][A-Za-z]{2}$", ErrorMessage = "A valid postcode is required")]
    public string Postcode { get; set; }

The view snippet is:

<div class="editor-label control-label">
  @Html.LabelFor(m => m.perinatalWomanView.Postcode)
</div>
div class="editor-field controls">
  @Html.EditorFor(m => m.perinatalWomanView.Postcode)
  @Html.ValidationMessageFor(m => m.perinatalWomanView.Postcode)
</div>

and the validation controller is:

public class ValidationController : Controller
{
    //
    // GET: /Validation/Validation/

    [HttpGet]
    public JsonResult PostcodeCheck(string Postcode)
    {

        //  postcode has already been checked for correct format
        //  now look it up to see if it exists

        string mbrraceCommonCodeEntitiesConnectionString = ConfigurationManager.ConnectionStrings["MbrraceCommonCodeEntities"].ConnectionString;
        if (PostcodeChecks.CheckPostcodeExists(mbrraceCommonCodeEntitiesConnectionString, Postcode))
        { return Json(true, JsonRequestBehavior.AllowGet); }

        return Json("This postcode was not found in the database", JsonRequestBehavior.AllowGet);

    }

When the controller is called the value of Postcode is null. The actual call - from Firebug - is:

http://localhost:57881/Validation/Validation /PostcodeCheck?perinatalWomanView.Postcode=OX4+1SU

How do I read the postcode string parameter correctly becuase it is clearly not null?

HELP!

Answer 1

You could have a view model like this:

public class AddressViewModel
{
    public string Postcode { get; set; }
}

and then use specify the Prefix by decorating the parameter with the [Bind] attribute:

[HttpGet]
public ActionResult PostcodeCheck(
    [Bind(Prefix = "perinatalWomanView")]AddressViewModel model
)
{
    // use model.Postcode here ...
}

or if you don't want to use the Bind attribute have the following models:

public class MyViewModel
{
    public AddressViewModel PerinatalWomanView { get; set; }
}

public class AddressViewModel
{
    public string Postcode { get; set; }
}

and then have your controller action take the view model:

[HttpGet]
public ActionResult PostcodeCheck(MyViewModel model)
{
    // use model.PerinatalWomanView.Postcode here ...
}