title: EF LINQ select entities where Id is in List
body: <p>I was trying to select a list of  entities using EF and Linq and I should retrieve only those that has a specific AccountId inside the Participants ICollection </p>
  
  <pre><code>public class Conversation
  {
      public Conversation()
      {
          Participants = new List&lt;Account&gt;();
          Messages = new List&lt;Message&gt;();
      }
  
      [Key]
      public Int32 conversationId { get; set; }
      public ICollection&lt;Message&gt; Messages { get; set; }
      public ICollection&lt;Account&gt; Participants { get; set; }
  }
  </code></pre>
  
  <p>_Db is DbContext </p>
  
  <pre><code>public async Task&lt;List&lt;Conversation&gt;&gt; FindByAccountIdAsync(Int32 id)
  {
     return await _Db.Conversations.Where(....).ToListAsync(); 
     // .... select conversations where id == AccountId inside ICollection&lt;Account&gt; Participants
  }
  </code></pre>
  
  <p>I have no idea on how to compose the query in LINQ</p>