IN clause in Lambda expression against a List as reference

Question

How to use IN clause having a list as reference?

List<PostOrcamentoServico> lOrcamentos = db.PostOrcamentoServico.Where(o => !o.Post.Usuarios.UsuEmail.Contains(User.Identity.Name) &&
                                                                       usuario.Clientes.Servicos.Contains(o.Servicos))
                                                                       .ToList();

in the above example, o.Servicos is a list.

Resuming: What I dould like to know how to do is use IN, however, using a list as reference:

myList.Contains(anotherList)

possible duplicate of [LINQ to SQL in and not in](http://stackoverflow.com/questions/3047657/linq-to-sql-in-and-not-in) — Arcturus, Aug 21 '15 at 14:20
@Arcturus No, it isn't what I am looking for... I want a List as reference, and I am using Lambda not Linq — Dan, Aug 21 '15 at 14:22
The lambda syntax and the query syntax are convertible and interchangeable. Having said that, it sounds like you're not simply looking to ensure a single value is contained in the list but rather the entire list is contained within the larger set. Is that correct? Your assertion that you "want a List as reference" isn't really clear. — Craig W., Aug 21 '15 at 14:26
possible duplicate of [Linq query list contains a list](http://stackoverflow.com/questions/2364090/linq-query-list-contains-a-list) — Dan, Aug 21 '15 at 14:31

Fabienne B. · Answer 1 · 2015-08-24T08:19:16.590

2

From memory, you can do :

bool b = anotherList.All(x=> myList.Contains(x));

[EDIT] here a full test sample:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ConsoleApplication1
{
    public class Program
    {
        public static void Main(string[] args)
        {
            List<string> l1 = new List<string>();   

            l1.Add("toto");l1.Add("titi") ;l1. Add("tata") ;l1.Add("tutu") ;l1.Add("tete");

            List<string> l2 = new List<string>();
            l2.Add("toto"); l2.Add ("titi"); l2.Add ( "tata") ;

            if (l2.All(l1.Contains))
            {
                System.Console.WriteLine("OK");
            }
            else 
            {
                System.Console.WriteLine("KO");
            }

        }
    }
}

edited Aug 24 '15 at 08:19

answered Aug 21 '15 at 14:37

Fabienne B.

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1
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{"Unable to create a constant value of type 'Servicili.Models.Servicos'. Only primitive types or enumeration types are supported in this context."} – Dan Aug 21 '15 at 15:34
If you are using custom object into your lists you should override `Equals(Object obj)` in order to make `Contains` work. – Fabienne B. Aug 24 '15 at 08:40

score 0 · Answer 2 · edited May 23 '17 at 11:44

0

use this :

bool contained = !subset.Except(superset).Any();

reference :

Determine if a sequence contains all elements of another sequence using Linq

edited May 23 '17 at 11:44

Community

1
1

answered Aug 21 '15 at 14:35

sm_

2,572
2
17
34

score 0 · Accepted Answer · answered Aug 24 '15 at 12:45

the right answer is this:

First: I get a list of items to compare:

var servicios = usuario.Clientes.Servicos.Select(s => s.SerId);

then I use this list with values to compare in my IN:

List<PostOrcamentoServico> lOrcamentos = db.PostOrcamentoServico.Where(os => !os.Post.Usuarios.UsuEmail.Contains(User.Identity.Name)&&
                                                                                      os.Servicos.All(s => servicios.Contains(s.SerId))).ToList();

IN clause in Lambda expression against a List as reference

3 Answers3