title: Why EF core tell me 'specified member is unmapped'?
body: <p>I want to filter users by name and return a new DTO by using the projection query (by Select):</p>
  <pre><code>var result = context.Users
      .Where(user =&gt; user.FullName == search)
      .Select(u =&gt; new UserPagingViewModel
      {
          Id = u.Id,
          IsSearchable = u.IsSearchable,
          FirstName = u.FirstName,
          LastName = u.LastName,
          FullName = u.FullName,
          Photo200 = u.Photo200,
          City = u.City,
          About = u.About,
          Skills = u.UserSkills.Select(us =&gt; us.Skill.Name),
          IsTeamMember = u.UserTeams.Any(ut =&gt; ut.UserAction == UserActionEnum.JoinedTeam)
      })
      .ToList();
  </code></pre>
  <p>User class:</p>
  <pre><code>public class User : IHasId
  {
      public long Id { get; set; }
      public string FirstName { get; set; }
      public string SecondName { get; set; }
      public string LastName { get; set; }
      public string City { get; set; }
      public string About { get; set; }
      public string Telegram { get; set; }
      public string Email { get; set; }
      public string Mobile { get; set; }
      public string FullName =&gt; FirstName + &quot; &quot; + SecondName + &quot; &quot; + LastName;
      public string Photo100 { get; set; }
      public string Photo200 { get; set; }
      public bool IsModerator { get; set; }
      public List&lt;UserTeam&gt; UserTeams { get; set; }
      public List&lt;UserSkill&gt; UserSkills { get; set; }
  
      [NotMapped]
      public List&lt;Team&gt; TeamsToRecruit { get; set; }
      [NotMapped]
      public bool AnyTeamOwner { get; set; }
  }
  </code></pre>
  <p>Data Base is <code>PostgreSql</code>. Data provider <code>PostgreSQL/Npgsql provider for Entity Framework Core</code></p>
  <p>But when I try to execute this request, I get an exception with the following message:</p>
  <blockquote>
  <p>The LINQ expression 'DbSet&lt;User&gt;()
  .Where(u =&gt; user.FullName == search)' could not be translated. Additional information: Translation of member 'FullName' on entity type 'User'
  failed. This commonly occurs when the specified member is unmapped.
  Either rewrite the query in a form that can be translated, or switch
  to client evaluation explicitly by inserting a call to 'AsEnumerable',
  'AsAsyncEnumerable', 'ToList', or 'ToListAsync'. See
  <a href="https://go.microsoft.com/fwlink/?linkid=2101038" rel="nofollow noreferrer">https://go.microsoft.com/fwlink/?linkid=2101038</a> for more information.</p>
  </blockquote>
  <p>I don't want use client evaluation.
  If I compare for example the FirstName property everything works fine.</p>
  <p>Please help me figure out how to solve this problem.</p>