public static void LinqToEntity()
        {
            ProductDBContext context = new ProductDBContext();
            var EconProducts         = from product in context.Products
                                       where product.Price < 50
                                       select product;

            foreach (var product in EconProducts)
            {
                Console.WriteLine("ProductID:{0},Name:{1},Price:{2}", product.ProductID, product.Name, product.Price);
            }
        }
        static void Main(string[] args)
        {
            ProductDBContext Context = new ProductDBContext();

            LinqToEntity();
        }