title: JSON circular reference in asp mvc 5
body: <p>I am getting an a Circular Reference Serialization Error and failed to load result...status of 500.</p>
  
  <p>I'm trying to create a dynamic dropdown list with the options from the database, appending options with js. </p>
  
  <p>those are my class:<i></p>
  
  <pre><code>public class IdentificacionViewModel
  { public virtual Causas Causas { get; set; }
    public virtual Identificacion Idententificacion { get; set; }
  } 
  
  
  public partial class Causas
  { 
  
  
      public int Id { get; set; }
      public string Causa { get; set; }
      public string Agente { get; set; }
      public Nullable&lt;int&gt; Id_Subproceso { get; set; }
      public Nullable&lt;int&gt; Id_identificacion { get; set; }
  
      public virtual Identificacion Identificacion { get; set; }
      public virtual Subprocesos Subprocesos { get; set; }
  }
  
  public Identificacion()
      {
          this.Causas = new HashSet&lt;Causas&gt;();
      }
  
      public int Id { get; set; }
      public string Nombre { get; set; }
      public Nullable&lt;int&gt; Id_Servicio { get; set; }
      public string Etapa { get; set; }
      public string Riesgo { get; set; }
      public string EfectoProb { get; set; }
  
      public virtual ICollection&lt;Causas&gt; Causas { get; set; }
      public virtual Servicios Servicios { get; set; }
      public virtual Impacto Impacto { get; set; }
  }
  </code></pre>
  
  <p></i></p>
  
  <p>my controller is:</p>
  
  <pre><code>public ActionResult GetA()
      {
          var category = db.Causas.ToList();
           return Json(category, JsonRequestBehavior.AllowGet);
      }
  </code></pre>
  
  <p>i don't know what could be the problem and thanks for the help.</p>