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 ;
                 }
                 int hashProductName = product.Name == null ?  : 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);
            }
        }