public static void linq6()
        {
            //Create linq query which returns all categories together with their products
            //Create class CategoryWithProduct which should keep the result the class CategoryWithProduct must conrtain the following
            //properties : CategoryName : string, ProductNames : List<string>, CategoryId : int
            List <Product>  listOfProducts   = Product.GetProducts;
            List <Category> listOfCategories = Category.GetCategories;

            var listOfAllProdsAndCates =
                from cate in listOfCategories
                join prod in listOfProducts on cate.CategoryID equals prod.CategoryID
                orderby cate.CategoryID
                select new { cate.CategoryID, prod.ProductID, prod.Name, cate.CategoryName };



            foreach (var item in listOfAllProdsAndCates)

            {
                CategoryWithProduct catewprod = new CategoryWithProduct(item.CategoryName, item.ProductID, listOfProducts);
                Console.WriteLine(item.CategoryID + "product ID is " + item.ProductID + ", " + item.Name);
            }
        }
        public static void linq6()
        {
            //Create linq query which returns all categories together with their products
            //Create class CategoryWithProduct which should keep the result the class CategoryWithProduct must conrtain the following
            //properties : CategoryName : string, ProductNames : List<string>, CategoryId : int
            List<Product> listOfProducts = Product.GetProducts;
            List<Category> listOfCategories = Category.GetCategories;

            var listOfAllProdsAndCates =
                from cate in listOfCategories
                join prod in listOfProducts on cate.CategoryID equals prod.CategoryID
                orderby cate.CategoryID
                select new { cate.CategoryID, prod.ProductID,prod.Name,cate.CategoryName };

            foreach (var item in listOfAllProdsAndCates)

            {
                CategoryWithProduct catewprod = new CategoryWithProduct(item.CategoryName, item.ProductID, listOfProducts);
                Console.WriteLine(item.CategoryID + "product ID is " + item.ProductID + ", " + item.Name);
            }
        }