Update data using LINQ

Question

I read that LINQ should be used for queries, but in the context below, the best way I found to update was by using the let.

var produtos = from o in orcItens    
    join p in Produtos on o.Id equals p.Id   
    let x = p.Estoque -= o.Quantidade
    select p;

• Produtos is a class IQueryable<> that will be persisted.
• orcItens is a list of ids, quantidade of the products sold

There is another way to update the data using lambda, for example?

I tried to use foreach but I could not get the data grouped.

Answer 1

LINQ -> Language-Integrated QUERY

Query -> Query

It’s even possible, but LINQ was created to make queries. Do not try to subvert your function, especially without deeply mastering its functioning and the consequences of doing this.

Go of foreach (command) and be happy. Obviously you can use LINQ to select what you will update.

Be careful not to complicate the design of the application just to facilitate the use of LINQ. Do the best for the model, if LINQ does not fit in it, bad luck of LINQ.

Answer 2

LINQ is a query-only language, it "does not allow" you to make changes to data collections.

So to solve your problem the ideal would be to make a query for the "products" that correspond to the "budgets", put this result in an object and at the end of the query join all these objects in a collection. Then I would use a foreach in this collection to update the data.

See the example below for how to do this. Suppose you have the classes below:

public class Produto
{
    public int Id { get; set; }
    public int Estoque { get; set; }
}

public class Orcamento
{
    public int Id { get; set; }
    public int Quantidade { get; set; }
}

Set a class to make the association between the "product" and the corresponding "budget":

public class ProdutoOrcamento
{
    public Produto Produto { get; set; }
    public Orcamento Orcamento { get; set; }
}

Make the query, store the result, and through a foreach update the data in the Product instance:

var produtosOrcamentos = (from o in orcamentos
                          join p in produtos on o.Id equals p.Id
                          select new ProdutoOrcamento { Produto = p, Orcamento = o });

foreach (var i in produtosOrcamentos)
{
    i.Produto.Estoque = i.Orcamento.Quantidade;
}