Hi!

I'm new to MVC3 and I'm looking for a web user control equivalent, I've been told that partial view is the way to go.

Now I'm trying to retrieve data from a partial view to submit it with a form.

I have two models, and one is the property of the other:

namespace AE.Tps.Models
{
    public class Movie
    {
        public string MovieTitle { get; set; }
        public Category MovieCategory { get; set; }
    }

    public class Category
    {
        public bool Action { get; set; }
        public bool Comedy { get; set; }
        public bool Thriller { get; set; }
        public bool Drama { get; set; }
        public bool SciFi { get; set; }
        public bool Horror { get; set; }
    }
}

The controller creates a default model for the starting page (Index) and also handles the HttpPost:

namespace AE.Tps.Controllers
{
    public class MovieController : Controller
    {
        public ActionResult Index()
        {
            Movie defaultMovie = new Movie() { MovieCategory = new Category(), MovieTitle = string.Empty };
            return View(defaultMovie);
        }

        [HttpPost]
        public ActionResult Index(Movie movie)
        {
            return View();
        }
    }
}

The view takes the model Movie and creates a form:

@model AE.Tps.Models.Movie

@using (Html.BeginForm())
{
    @Html.Partial("_MoviePartial", Model)
    <input type="submit" />
}

Under the Views/Shared folder, I have added two partial views, _MoviePartial:

@model AE.Tps.Models.Movie

@Html.TextBoxFor(model => Model.MovieTitle)
@Html.Partial("_CategoryPartial", Model.MovieCategory)

...and _CategoryPartial:

@model AE.Tps.Models.Category

@Html.CheckBoxFor(model => Model.Action)
@Html.CheckBoxFor(model => Model.Comedy)
@Html.CheckBoxFor(model => Model.Drama)
@Html.CheckBoxFor(model => Model.Horror)
@Html.CheckBoxFor(model => Model.SciFi)
@Html.CheckBoxFor(model => Model.Thriller)

When I run the app, I get the exception : Object reference not set to an instance of an object.

I add a breakpoint in the controller, at the second Index method (HttpPost), to see the Movie data but I can only get the title, the categories I've checked are gone and the Category = null.

Do I have to create a new model which includes both models and pass that on to the partial view? But what if I want to use only the _CategoryPartial on another view, then I would need to give it more data than necessary.