error with decimal in mvc3 - the value is not valid for field

Question

I'm following [Getting started with ASP.NET MVC 3][1]. And I can't add/edit with value of Price = 9.99 or 9,99. It said: "The value '9.99' is not valid for Price." and "The field Price must be a number."

How to fix this?

Model:

    public class Movie
{
    public int ID { get; set; }
    public string Title { get; set; }
    public DateTime ReleaseDate { get; set; }
    public string Genre { get; set; }
    public decimal Price { get; set; }
}

public class MovieDbContext : DbContext
{
    public DbSet<Movie> Movies { get; set; }
}

Controller:

public class MovieController : Controller
{
    private MovieDbContext db = new MovieDbContext();

    //
    // GET: /Movie/

    public ViewResult Index()
    {
        var movie = from m in db.Movies
                     where m.ReleaseDate > new DateTime(1984, 6, 1)
                     select m;

        return View(movie.ToList()); 
    }

    //
    // GET: /Movie/Details/5

    public ViewResult Details(int id)
    {
        Movie movie = db.Movies.Find(id);
        return View(movie);
    }

    //
    // GET: /Movie/Create

    public ActionResult Create()
    {
        return View();
    } 

    //
    // POST: /Movie/Create

    [HttpPost]
    public ActionResult Create(Movie movie)
    {
        if (ModelState.IsValid)
        {
            db.Movies.Add(movie);
            db.SaveChanges();
            return RedirectToAction("Index");  
        }

        return View(movie);
    }

    //
    // GET: /Movie/Edit/5

    public ActionResult Edit(int id)
    {
        Movie movie = db.Movies.Find(id);
        return View(movie);
    }

    //
    // POST: /Movie/Edit/5

    [HttpPost]
    public ActionResult Edit(Movie movie)
    {
        if (ModelState.IsValid)
        {
            db.Entry(movie).State = EntityState.Modified;
            db.SaveChanges();
            return RedirectToAction("Index");
        }
        return View(movie);
    }

    //
    // GET: /Movie/Delete/5

    public ActionResult Delete(int id)
    {
        Movie movie = db.Movies.Find(id);
        return View(movie);
    }

    //
    // POST: /Movie/Delete/5

    [HttpPost, ActionName("Delete")]
    public ActionResult DeleteConfirmed(int id)
    {            
        Movie movie = db.Movies.Find(id);
        db.Movies.Remove(movie);
        db.SaveChanges();
        return RedirectToAction("Index");
    }

    protected override void Dispose(bool disposing)
    {
        db.Dispose();
        base.Dispose(disposing);
    }
}
}

View:

    @model MvcMovies.Models.Movie

@{
ViewBag.Title = "Create";
}

<h2>Create</h2>

<script src="@Url.Content("~/Scripts/jquery.validate.min.js")" type="text/javascript">       </script>
<script src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")" type="text/javascript"></script>

@using (Html.BeginForm()) {
@Html.ValidationSummary(true)
<fieldset>
    <legend>Movie</legend>

    <div class="editor-label">
        @Html.LabelFor(model => model.Title)
    </div>
    <div class="editor-field">
        @Html.EditorFor(model => model.Title)
        @Html.ValidationMessageFor(model => model.Title)
    </div>

    <div class="editor-label">
        @Html.LabelFor(model => model.ReleaseDate)
    </div>
    <div class="editor-field">
        @Html.EditorFor(model => model.ReleaseDate)
        @Html.ValidationMessageFor(model => model.ReleaseDate)
    </div>

    <div class="editor-label">
        @Html.LabelFor(model => model.Genre)
    </div>
    <div class="editor-field">
        @Html.EditorFor(model => model.Genre)
        @Html.ValidationMessageFor(model => model.Genre)
    </div>

    <div class="editor-label">
        @Html.LabelFor(model => model.Price)
    </div>
    <div class="editor-field">
        @Html.EditorFor(model => model.Price)
        @Html.ValidationMessageFor(model => model.Price)
    </div>

    <p>
        <input type="submit" value="Create" />
    </p>
</fieldset>
}

<div>
@Html.ActionLink("Back to List", "Index")
</div>
public DbSet<Movie> Movies { get; set; }
}

Answer 1

I just stumbled on this again after 2 years. I thought ASP.NET MVC 5 had solved this but looks like it's not the case. So here goes how to solve the problem...

Create a class called DecimalModelBinder like the following and add it to the root of your project for example:

using System;
using System.Globalization;
using System.Web.Mvc;

namespace YourNamespace
{   
    public class DecimalModelBinder : IModelBinder
    {
        public object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
        {
            ValueProviderResult valueResult = bindingContext.ValueProvider
                .GetValue(bindingContext.ModelName);

            ModelState modelState = new ModelState { Value = valueResult };

            object actualValue = null;

            if(valueResult.AttemptedValue != string.Empty)
            {
                try
                {
                    actualValue = Convert.ToDecimal(valueResult.AttemptedValue, CultureInfo.CurrentCulture);
                }
                catch(FormatException e)
                {
                    modelState.Errors.Add(e);
                }
            }

            bindingContext.ModelState.Add(bindingContext.ModelName, modelState);

            return actualValue;
        }
    }
}

Inside Global.asax.cs, make use of it in Application_Start() like this:

ModelBinders.Binders.Add(typeof(decimal?), new DecimalModelBinder());