usingcustomgridrenderer.cs

@using (Html.BeginForm("PostData", "Home", FormMethod.Post, new { id = "simpleForm" }))
{
    @(Html.Grid(Model.Items)
          .RenderUsing(new PostAsListRenderer<ItemModel>("list"))
          .Columns(c =>
          {
              c.For(x => Html.Partial("Grid/Id", x)).Named("Id");
              c.For(x => Html.Partial("Grid/Name", x)).Named("Name");
              c.For(x => Html.Partial("Grid/Description", x)).Named("Description");
              c.For(x => Html.Partial("Grid/SelectedItem", new ListModel { SelectedItem = x.SelectedItem, SelectListItems = Model.SelectListItems })).Named("DropDown");
          }))

    <input type="submit" value="submit" id="btnSubmit" />
}