public bool AddProduct(int ProductId) { var findItem = this.cartItems .Where(s => s.Id == ProductId) .Select(s => s) .FirstOrDefault(); if (findItem == default(Models.Cart.CartItem)) { using (Models.CartsServerEntities db = new CartsServerEntities()) { var product = (from s in db.Products where s.Id == ProductId select s).FirstOrDefault(); if (product != default(Models.Product)) { this.AddProduct(product); } } } else { findItem.Quantity += 1; } return(true); }