视图mvc .NET上的null引用异常

Question

我有一个填充的数据库，但是当我想在视图中返回单个值时，Visual Studio指向System.NullReferenceException＆＃39;发生在App_Web_qoycb13m.dll但未在用户代码中处理。为什么会这样？

错误行是：

<h2>@Model.Name</h2>

控制器：

    public ActionResult Detail(int? MovieID)
    {
        var movie = _movie.Movies.Include(m => m.Genre).SingleOrDefault(m => m.Id == MovieID);
        return View(movie);
    }

观点：

    @model Viddly.Models.Movie

    @{
        ViewBag.Title = "Detail";
        Layout = "~/Views/Shared/_Layout.cshtml";
    }

    <h2>@Model.Name</h2>

索引页面，按MovieID单击并更改页面：

    @model IEnumerable<Viddly.Models.Movie>
@{
    ViewBag.Title = "Movie";
    Layout = "~/Views/Shared/_Layout.cshtml";
}

<h2>Movies</h2>


<table class="table table-bordered table-hover">
    <tbody>
        <thead>
            <tr>
                <th>Movies</th>
                <th>Genre</th>
            </tr>
        </thead>
        @foreach (var movie in Model)
        {
            <tr>

                <td>@Html.ActionLink(movie.Name, "Detail", new { movie.Id})</td>
                <td>@movie.Genre.GenreType</td>
            </tr>
        }
    </tbody>

</table>

它的我的RouteConfig.cs：

 routes.IgnoreRoute("{resource}.axd/{*pathInfo}");



        routes.MapRoute(
            name: "CustomerDetails",
            url: "{controller}/{Detail}/{CustomerID}",
            defaults: new { controller = "Customer", action = "Detail" }
        );

        routes.MapRoute(
           name: "MovieDetails",
           url: "{controller}/{Detail}/{MovieID}",
           defaults: new { controller = "Movie", action = "Detail" }
       );

        routes.MapRoute(
            name: "Default",
            url: "{controller}/{action}/{id}",
            defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }
        );

EDITED