Custom Model Binder for ASP.NET MVC on GET request

Question

I've created a custom MVC Model Binder which gets called for every HttpPost that comes into the server. But does not get called for HttpGet requests.

• Should my custom model binder get called during a GET? If so, what did I miss?
• If not, How can I write custom code handling the QueryString from a GET Request?

Here's my implementation...

public class CustomModelBinder : DefaultModelBinder
{
   public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
   {
      // This only gets called for POST requests. But I need this code for GET requests.
   }
}

Global.asax

protected void Application_Start()
{
   ModelBinders.Binders.DefaultBinder = new CustomModelBinder();
   //...
}

I've looked into these solutions, but they don't quite work for what I'm looking for:

• Persisting complex types via TempData
• Using the default binder to build up complex types (?Name=John&Surname=Doe)

Remark on answer

Thanks to @Felipe for the help. Just in case someone struggles with the same, I learnt:

• The custom model binder CAN be used for GET requests
• You CAN use DefaultModelBinder class
• My snag was that the action method MUST have a parameter (otherwise the model binder is skipped for GET Requests, which makes sense when you think about it)

Answer 1

Let's supose you have your own type you want to bind.

public class Person
{
    public int Id { get; set; }
    public string Name { get; set; }
    public int Age { get; set; }
    // other properties you need
}

You can create a custom model bind for this specific type, inherithing from DefaultModelBinder, for sample:

public class PersonModelBinder : DefaultModelBinder
{
    public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
    {
        var request = controllerContext.HttpContext.Request;

        int id = Convert.ToInt32(request.QueryString["id"]);
        string name = request.QueryString["name"];
        int age = Convert.ToInt32(request.QueryString["age"]);
        // other properties

        return new Person { Id = id, Name = name, Age = age };
    }
}

In the Global.asax in the Application_Start event, you can registry this model bind, for sample:

// for Person type, bind with the PersonModelBinder
ModelBinders.Binders.Add(typeof(Person), new PersonModelBinder());

In the BindModel method from the PersonModelBinder, make sure you have all parameters in the querystring and give them the ideal treatment.

Since you have this action method:

public ActionResult Test(Person person)
{
  // process...
}

You can access this action with an url something like this:

Test?id=7&name=Niels&age=25