OData order by navigation属性

我想消费 Northwind ASP.NET MVC项目中的OData服务,并使用WebGrid控件进行可视化。我使用服务URL使用Visual Studio 2012创建服务引用。问题在于WebGrid的排序。当我尝试在导航字段(如CategoryName)上对其进行排序时,我收到一个错误:“类型'Product'中不存在'CategoryName'属性或字段”。我理解错误,但我不知道如何使其工作并获得所需的部分数据。如有任何帮助,我们将不胜感激。 控制器:

private ODataNorthwind.NorthwindEntities context = new ODataNorthwind.NorthwindEntities(new Uri("http://services.odata.org/Northwind/Northwind.svc"));
    //
    // GET: /Odata/

    public ActionResult WebGrid(int page = 1, int rowsPerPage = 10, string sort = "ProductID", string sortDir = "ASC")
    {
        var data = GetProducts(page, rowsPerPage, sort, sortDir);
        return View(data);
    }

    // Data for WebGridObj
    private WebGridViewModel GetProducts(int page = 1, int rowsPerPage = 10, string sort = "ProductID", string sortDir = "ASC")
    {
        var query = context.Products.OrderBy(sort + " " + sortDir)
            .Select(p => new
            {
                p.ProductID,
                p.ProductName,
                p.Category.CategoryName,
                p.Supplier.CompanyName,
                p.Supplier.Country
            });

        WebGridViewModel model = new WebGridViewModel
        {
            TotalRows = query.Count(),
            Products = query.Skip((page - 1) * rowsPerPage).Take(rowsPerPage).ToList().Select(p =>
               new HtmlViewModel
               {
                   ProductId = p.ProductID,
                   ProductName = p.ProductName,
                   CategoryName = p.CategoryName,
                   CompanyName = p.CompanyName,
                   Country = p.Country
               })
        };
        return model;
    }

视图:

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

<h2>OData WebGrid</h2>

<div>
@{
    var grid = new WebGrid(null, defaultSort: "ProductId");
    grid.Bind(Model.Products, rowCount: Model.TotalRows, autoSortAndPage: false);
}
@grid.GetHtml(columns: grid.Columns(
    grid.Column("ProductId"),
    grid.Column("ProductName"),
    grid.Column("CategoryName"),
    grid.Column("CompanyName"),
    grid.Column("Country")
    ))
</div>