entitydatasource concect to gridview

using (Entitiestak db = new Entitiestak())
                {  
                       var query = (db.V_Tproduct_brandcategory_category
                       .OrderByDescending(x => x.ID_Pk_Product)
                       .Take(1).ToList())
                       .Single();
                 }

DetailsView1.DataSource =