Compare two lists of objects and pick only the different ones

Question

I’m having trouble comparing two lists of the same kind List<Produto> in my product class I have the following structure.

public class Product
    {
        public int IdProduct { get; set; }
        public String Name { get; set; }

        public Supplier supplier { get; set; }

        public Product(){}
    }

And in my class of Supplier have:

public class Supplier
{
    public int IdSupplier { get; set; }
    public string Main { get; set; }
    public string Name { get; set; }
}

And I get an initial list, and an ending. The final contains more product elements.

Testing

List<Product> listaProdutosDiferentes = listaPrincipalProdutos.Union(listaFinalProdutos).ToList();

However this test only concatenated the two lists and not taking forming a list with products different from each other.

Editing

I have two lists, the first has some products may be (id;name) 1, Motorola One Mobile Phone; 2, Motorola G6 Cellular; 3, Motorola E5 cell phone;

On my second list you will have the same list as the first (Not necessarily following a sequence).

5, Samsung Galaxy Cell Phone; 1, Motorola One Mobile Phone; 2, Motorola G6 Cellular; 3, Motorola E5 Cellular; 4, Cellular Iphone 6S;

My final list needs to be

1, Motorola One Mobile Phone; 2, Motorola G6 Cellular; 3, Motorola E5 Cellular; 4, Cellular Iphone 6S; 5, Samsung Galaxy Cell Phone;

Why do I do that? so that when a person goes to make a search in my system, the system presents first the research that the client made, example "Motorola Cellular", and then the other items that have a relationship, in this case other cell phones.

[Duplicate]

Marked as duplicate, but in the answer that left not solved my problem I did the proposed codes, however all do not exclude the item that already has in the other list, I will show by images:

Here are 4 products.

Here are 9 products

And on my list that should be the different list contains 9 products and not 5

Answer 1

You must use the Except() of LINQ, which I use joins the lists without distinguishing what is already in the other.

var listaProdutosDiferentes = listaPrincipalProdutos.Except(listaFinalProdutos);

On the other hand I may want this (I have no way to say, the question is a little ambiguous, see which produces the result you expect):

var listaProdutosDiferentes = listaPrincipalProdutos.Except(listaFinalProdutos).Concat(listaFinalProdutos.Except(listaPrincipalProdutos));

Or still use the Intersect():

var listaProdutosDiferentes = listaPrincipalProdutos.Intersect(listaFinalProdutos);

I put in the Github for future reference.

Another point is that you should only use ToList() when you really need to make the list, it may even be your case, I have no way of disputing that, but it may not be necessary, so I chose not to use.