title: Web Api returns only one child object from one to many relationship using Entity Framework
body: <p>I've got a controller method that must return parent object with collection of children. In debug I can see plenty of children during execution but when I catch a json it has only one child.</p>
  
  <pre><code>    [Route("api/page/{id}")]
      public JsonResult GetPage(int id)
      {
          var item = db.Pages.Include(p =&gt; p.PageContainerTemplates)
              .SingleOrDefault(p =&gt; p.Id == id);
          return Json(item);
      }
  </code></pre>
  
  <p>I've got many children and Entity Framework Core get them all but response json looks like this:</p>
  
  <pre><code>{
    "name": "Index",
    "bodyClasses": "full-width-container transparent-header",
    "title": "Index",
    "pageContainerTemplates": [
      {
        "position": 8,
        "pageId": 1
      }
    ]
  }
  </code></pre>
  
  <p>Parent object looks like this:</p>
  
  <pre><code>public class Page : BaseEntity
  {
      public string Name { get; set; }
      public string BodyClasses { get; set; }
      public string Title { get; set; }
      public virtual List&lt;PageContainerTemplate&gt; PageContainerTemplates { get; set; } 
  }
  </code></pre>
  
  <p>And child looks like this:</p>
  
  <pre><code>public class PageContainerTemplate : BaseEntity
  {
      public int Position { get; set; }
      public int PageId { get; set; }
      public Page Page { get; set; }
      public int ContainerTemplateId { get; set; }
      public ContainerTemplate ContainerTemplate { get; set; }
  }
  </code></pre>
  
  <p>I haven't got any additional relationships or any alternative keys but what is strange is than my only child in json haven't got a "containerTemplateId" attribute</p>