MVC Model Binding to a collection where collection does not begin with a 0 index

Question

I'm trying to perform remote validation on a property of an item within a collection. The validation works OK on the first item of the collection. The http request to the validation method looks like:

/Validation/IsImeiAvailable?ImeiGadgets[0].ImeiNumber=123456789012345

However on the 2nd item where the url looks like below, the validation doesn't work

/Validation/IsImeiAvailable?ImeiGadgets[1].ImeiNumber=123456789012345

Now I'm pretty sure the reason for this, is that binding wont work on a collection that doesn't begin with a zero index.

My validation method has a signature as below:

public JsonResult IsImeiAvailable([Bind(Prefix = "ImeiGadgets")] Models.ViewModels.ImeiGadget[] imeiGadget)

Because I'm passing an item within a collection I have to bind like this yet what I'm really passing is just a single value.

Is there anyway I can deal with this other than just binding it as a plain old query string.

Thanks

Edit: This is the quick fix to get the Imei variable but I'd rather use the model binding:

string imeiNumber = Request.Url.AbsoluteUri.Substring(Request.Url.AbsoluteUri.IndexOf("=")+1);

Edit: Here is my ImeiGadget class:

public class ImeiGadget
{
    public int Id { get; set; }

    [Remote("IsImeiAvailable", "Validation")]
    [Required(ErrorMessage = "Please provide the IMEI Number for your Phone")]
    [RegularExpression(@"(\D*\d){15,17}", ErrorMessage = "An IMEI number must contain between 15 & 17 digits")]
    public string ImeiNumber { get; set; }
    public string Make { get; set; }
    public string Model { get; set; }
}

Answer 1

You could write a custom model binder:

public class ImeiNumberModelBinder : IModelBinder
{
    public object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
    {
        var modelName = bindingContext.ModelName;
        var request = controllerContext.HttpContext.Request;
        var paramName = request
            .Params
            .Keys
            .Cast<string>()
            .FirstOrDefault(
                x => x.EndsWith(modelName, StringComparison.OrdinalIgnoreCase)
            );

        if (!string.IsNullOrEmpty(paramName))
        {
            return bindingContext
                .ValueProvider
                .GetValue(request[paramName])
                .AttemptedValue;
        }

        return null;
    }
}

and then apply it to the controller action:

public ActionResult IsImeiAvailable(
    [ModelBinder(typeof(ImeiNumberModelBinder))] string imeiNumber
)
{
    return Json(!string.IsNullOrEmpty(imeiNumber), JsonRequestBehavior.AllowGet);
}

Now the ImeiGadgets[xxx] part will be ignored from the query string.