Entity Framework. Select only 1 from a list in the Include?

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Entity Framework. Select only 1 from a list in the Include?

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#1 by (0 votes)

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I'm trying to get just 1 record from the Phones and Emails lists.

var lista = Db.Oportunidades
    .Include(x => x.Conta.Proprietario)
    .Include(x => x.Conta.Contatos.Select(c => c.Telefones))
    .Include(x => x.Conta.Contatos.Select(c => c.Emails))
    .Include(x => x.Estado)
    .Include(x => x.Motivo)
    .Include(x => x.Tipo);

I have tried to use First() , Sigle() , Take(1) that generate the error below.

The Include path expression must refer to a navigation property defined on the type. Use dotted paths for reference navigation properties and the Select operator for collection navigation properties. Parameter name: path

Any tips?

c# entity-framework-6

asked by anonymous 05.12.2017 / 21:49

1 answer

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score 0 · Accepted Answer

It's impossible. The Include function does not support these types of operations.

You can use Select and return an anonymous type containing the master record, telephone number, and email.

Example:

var lista = Db.Oportunidades
    .Include(x => x.Conta.Proprietario)
    .Include(x => x.Estado)
    .Include(x => x.Motivo)
    .Include(x => x.Tipo)
    .Select(x => new 
    {
        Registro = x,
        Telefone = x.Conta.Contatos.Telefones.FirstOrDefault(),
        Email = x.Conta.Contatos.Emails.FirstOrDefault(),
    });