linq 之 Distinct的使用

        public class Product
        {
            public string Name { get;set;}
            public int Code { get; set; }
        }
        class ProductComparet : IEqualityComparer<Product>
        {
            public bool Equals(Product x, Product y)
            {
                if (object.ReferenceEquals(x,y))
                {
                    return true;
                }
                if (object.ReferenceEquals(x,null)||object.ReferenceEquals(y,null))
                {
                    return false;
                }
                return x.Code == y.Code && x.Name == y.Name;
            }

            public int GetHashCode(Product product)
            {
                if (object.ReferenceEquals(product, null))
                {
                    return 0;
                }
                int hashProductName = product.Name == null ? 0 : product.Name.GetHashCode();

                int hashProductCode = product.Code.GetHashCode();
                return hashProductName ^ hashProductCode;

            }
        }

        static void Main(string[] args)
        {
   
            Product[] products = { new Product { Name = "apple", Code = 9 }, 
                       new Product { Name = "orange", Code = 4 }, 
                       new Product { Name = "apple", Code = 9 }, 
                       new Product { Name = "lemon", Code = 12 } };

            IEnumerable<Product> noduplicates = products.Distinct(new ProductComparet());
            foreach (var item in noduplicates)
            {
                Console.WriteLine(item.Name+" "+item.Code);
            }
        }