using System;

using System.Collections.Generic;

using System.Linq;

​

public class Product

{

    public string Name { get; set; }

    public int Code { get; set; }

}

​

// Custom comparer for the Product class

class ProductComparer : IEqualityComparer<Product>

{

    // Products are equal if their names and product numbers are equal.

    public bool Equals(Product x, Product y)

    {

​

        //Check whether the compared objects reference the same data.

        if (Object.ReferenceEquals(x, y)) return true;

​

        //Check whether any of the compared objects is null.

        if (Object.ReferenceEquals(x, null) || Object.ReferenceEquals(y, null))

            return false;

​

        //Check whether the products' properties are equal.

        return x.Code == y.Code && x.Name == y.Name;

    }

​

    // If Equals() returns true for a pair of objects 

    // then GetHashCode() must return the same value for these objects.

​

    public int GetHashCode(Product product)

    {

        //Check whether the object is null

        if (Object.ReferenceEquals(product, null)) return 0;

​

        //Get hash code for the Name field if it is not null.

        int hashProductName = product.Name == null ? 0 : product.Name.GetHashCode();

​

        //Get hash code for the Code field.

        int hashProductCode = product.Code.GetHashCode();

​

        //Calculate the hash code for the product.

        return hashProductName ^ hashProductCode;

    }

​

}

​

public class Program

{

    public static void Main()

    {

        Product[] store1 = { new Product { Name = "apple", Code = 9 }, 

                       new Product { Name = "orange", Code = 4 },

                           new Product { Name = "orange", Code = 5 },

                           new Product { Name = "orange", Code = 6 },

                           new Product { Name = "orange", Code = 7 },

                           new Product { Name = "orange", Code = 8 },

                           new Product { Name = "orange", Code = 9 }};

​

Product[] store2 = { new Product { Name = "apple", Code = 9 } };

        IEnumerable<Product> duplicates =

    store2.Intersect(store1, new ProductComparer());

​

foreach (var product in duplicates)

    Console.WriteLine(product.Name + " " + product.Code);

    }

}