GridView does not show columns for complex fields in Custom Binding mode

[DX Support team: this thread was cloned from GridView - Сustom databinding issues]
Hello,

I'm trying the new custom binding mode on gridviews and I have several problems implementing it.
I try do display several objects which contain other objects. Here is a simplified example of what my objects looks like :

C#
public class Car  
{  
    public int id;  
    public Engine engine;  
    public string model;  
    public string brand;  
}  

public class Engine  
{  
    public int id;  
    public string brand;  
    public string model;  
    public int horsePower;  
}  

My first problem is that I am unable to display Engine properties in the gridview using custom databinding. In the method linked to the gridview's settings.CallbackRouteValues property, I use the GridViewExtension.GetViewModel method to get the gridview's viewmodel. When it is null, I create a new viewmodel and add the same columns that my gridview contains. Then I bind the viewmodel to my data using the ProcessCustomBinding method. My data is a List<Car>. It works well for Car simple attributes (id, model, brand). However I am not able to display Engine properties. When I use Linq databinding to display the engine's horsePower, all I have to do is to set the gridview's column fieldname to "Engine.horsePower" This method doesn't seem to work with this binding method. Do I have to manually feed each of the viewmodel field to achieve this? Thanks. Here is my controller code :

C#
public class CarController : Controller  
{  
    [HttpGet, ActionName(CarControllerAction.Car)]  
    public ActionResult Car()  
    {  
        return View(CarControllerAction.Car);  
    }  

    [AcceptVerbs(HttpVerbs.Get | HttpVerbs.Post), ActionName(CarControllerAction.Car_Partial)]  
    public PartialViewResult Car_Partial()  
    {  
        var viewModel = GridViewExtension.GetViewModel("gvCar");  
        if (viewModel == null)  
        {  
            viewModel = new GridViewModel();  
            viewModel.KeyFieldName = "ID";  

            viewModel.Columns.Add("ID");  
            viewModel.Columns.Add("Model");  
            viewModel.Columns.Add("Brand"); viewModel.Columns.Add("Engine.ID");  
            viewModel.Columns.Add("Engine.Brand");  
            viewModel.Columns.Add("Engine.Model");  
            viewModel.Columns.Add("Engine.HorsePower");  
        }  

        viewModel.ProcessCustomBinding(  
            MyBindingHandlers.MyGetDataRowCount,  
            MyBindingHandlers.MyGetData);  

        return PartialView(CarControllerAction.Car_Partial, viewModel);  
    }  

    [AcceptVerbs(HttpVerbs.Get | HttpVerbs.Post), ActionName(CarControllerAction.Car_Partial_Paging)]  
    public PartialViewResult Car_Partial_Paging(GridViewPagerState pager)  
    {  
        var viewModel = GridViewExtension.GetViewModel("gvCar");  
        viewModel.Pager.Assign(pager); // pager.PageIndex is always 0 ???!!!  
        viewModel.ProcessCustomBinding(  
            MyBindingHandlers.MyGetDataRowCount,  
            MyBindingHandlers.MyGetData);  
        return PartialView(CarControllerAction.Car_Partial, viewModel);  
    }  
}  



public class CarControllerAction  
{  
    public const string Car = "Car";  
    public const string Car_Partial = "Car_Partial";  
    public const string Car_Partial_Paging = "Car_Partial_Paging";  
}  



public static class MyBindingHandlers {  
    static IQueryable<Car> Model { get { return new CarDAO<Car>().GetAll_Query(); } }  

    public static void MyGetDataRowCount(GridViewCustomBindingGetDataRowCountArgs e) {  
        e.DataRowCount = Model.Count();  
    }  

    public static void MyGetData(GridViewCustomBindingGetDataArgs e) {  
        e.Data = Model  
            .Skip(e.StartDataRowIndex)  
            .Take(e.DataRowCount)  
            .ToList();  
    }  
}  

And here is my view :

C#
@model GridViewModel  

@Html.DevExpress().GridView(  
    settings =>  
    {  
        settings.Name = "gvCar";  

        settings.CallbackRouteValues = new {  
            Controller = "CarController",  
            Action = CarControllerAction.Car_Partial  
        };  
        settings.CustomBindingRouteValuesCollection.Add(  
            GridViewOperationType.Paging,  
            new {  
                Controller = "CarController",  
                Action = CarControllerAction.Car_Partial_Paging  
            }  
        );  

        settings.KeyFieldName = "ID";  
        settings.Width = System.Web.UI.WebControls.Unit.Percentage(100);  
        settings.Settings.ShowColumnHeaders = true;  
        settings.Settings.ShowFilterRow = true;  
        settings.Settings.ShowFilterRowMenu = true;  
        settings.Settings.ShowFooter = true;  
        settings.Settings.ShowGroupButtons = true;  
        settings.Settings.ShowGroupedColumns = true;  
        settings.Settings.ShowGroupPanel = true;  
        settings.Settings.ShowHeaderFilterButton = true;  
        settings.Settings.ShowTitlePanel = true;  
        settings.Settings.UseFixedTableLayout = true;  



        settings.SettingsBehavior.AllowDragDrop = true;  
        settings.SettingsBehavior.AllowFocusedRow = true;  
        settings.SettingsBehavior.AllowGroup = true;  
        settings.SettingsBehavior.AllowSort = true;  
        settings.SettingsBehavior.ColumnResizeMode = ColumnResizeMode.NextColumn;  
        settings.SettingsBehavior.ConfirmDelete = true;  
        settings.SettingsBehavior.EnableRowHotTrack = true;  



        settings.SettingsPager.FirstPageButton.Visible = true;  
        settings.SettingsPager.LastPageButton.Visible = true;  
        settings.SettingsPager.PageSize = 50;  
        settings.SettingsPager.PageSizeItemSettings.Visible = true;  
        settings.SettingsPager.PageSizeItemSettings.Items = new string[] { "10", "20", "50" };  



        settings.SettingsCookies.Enabled = true;  
        settings.SettingsCookies.CookiesID = settings.Name;  
        settings.SettingsCookies.StoreColumnsVisiblePosition = true;  
        settings.SettingsCookies.StoreColumnsWidth = true;  
        settings.SettingsCookies.StoreFiltering = true;  
        settings.SettingsCookies.StoreGroupingAndSorting = true;  
        settings.SettingsCookies.StorePaging = true;  



        settings.SettingsBehavior.EnableCustomizationWindow = true;  
        settings.SettingsPopup.CustomizationWindow.Height = 500;  
        settings.SettingsPopup.CustomizationWindow.Width = 250;  

        settings.Columns.Add(column => {  
            column.FieldName = "ID";  
            column.ColumnType = MVCxGridViewColumnType.TextBox;});  
        settings.Columns.Add(column => {  
            column.FieldName = "Model";  
            column.ColumnType = MVCxGridViewColumnType.TextBox;});  
        settings.Columns.Add(column => {  
            column.FieldName = "Brand";  
            column.ColumnType = MVCxGridViewColumnType.TextBox;});  
        settings.Columns.Add(column => {  
            column.FieldName = "Engine.ID";  
            column.ColumnType = MVCxGridViewColumnType.TextBox;});  
        settings.Columns.Add(column => {  
            column.FieldName = "Engine.Brand";  
            column.ColumnType = MVCxGridViewColumnType.TextBox;});  
        settings.Columns.Add(column => {  
            column.FieldName = "Engine.Model";  
            column.ColumnType = MVCxGridViewColumnType.TextBox;});  
        settings.Columns.Add(column => {  
            column.FieldName = "Engine.HorsePower";  
            column.ColumnType = MVCxGridViewColumnType.TextBox;});  
    }  
).BindToCustomData(Model).GetHtml()