c# outlook Sendeventhandler opening object only once

Question

In my application I use Outlook Sendeventhandler to capture the click on the "Send" button of the email in outlook and open a screen to register observation regarding the email that was sent.

I have the main class where I mail:

public partial class PendenciaConsulta : UserControl
{
   EmailEnviado emailEnviado = null;

   private void btnEnviarEmail_Click(object sender, RoutedEventArgs e)
   {
       foreach(string grupo in ListaGrupo)
       {
          emailEnviado = new EmailEnviado();

          emailEnviado.ListaPendenciaId = listaPendencia.Where(p=>p.ClienteGrupo == grupo).Select(p=>p.PendenciaId).ToList();
          emailEnviado.PendenciaConsulta = this;

          //Preparo o body
          // ....

          MailItem mailItem = app.CreateItem(OlItemType.olMailItem);

          ((Microsoft.Office.Interop.Outlook.ItemEvents_10_Event)mailItem).Send += new Microsoft.Office.Interop.Outlook.ItemEvents_10_SendEventHandler(emailEnviado.EmailEnviadoEvent);
          ((Microsoft.Office.Interop.Outlook.ItemEvents_10_Event)mailItem).Close += new Microsoft.Office.Interop.Outlook.ItemEvents_10_CloseEventHandler(emailEnviado.EmailCanceladoEvent);

          mailItem.BodyFormat = OlBodyFormat.olFormatHTML;

          mailItem.HTMLBody = body.ToString();
          mailItem.Display();
       }
   }
}

And the secondary class:

/// <summary>
/// Classe criada para poder receber a lista de ids de pendencias para ser tratadas no event.
/// </summary>
public class EmailEnviado
{
    public List<int> ListaPendenciaId { get; set; }
    public PendenciaConsulta PendenciaConsulta { get; set; }
    public int StatusId { get; set; }

    /// <summary>
    /// Construtor para receber os parametros necessários
    /// </summary>
    /// <param name="listaPendenciaId"></param>
    /// <param name="pendenciaConsulta"></param>
    /// <param name="isITM"></param>
    /// <param name="isRecepcao"></param>
    public EmailEnviado(List<int> listaPendenciaId, PendenciaConsulta pendenciaConsulta, MailItem mailItem)
    {
        this.ListaPendenciaId = listaPendenciaId;
        this.PendenciaConsulta = pendenciaConsulta;
    }

    /// <summary>
    /// Criado pois os booleans não estavam sendo enviador através do construtor
    /// </summary>
    public EmailEnviado()
    {

    }

    /// <summary>
    /// Captura o evento se o usuário fechou sem enviar
    /// </summary>
    /// <param name="Cancel"></param>
    public void EmailCanceladoEvent(ref bool Cancel)
    {

    }

    public void EmailEnviadoEvent(ref bool Cancel)
    {
        Console.WriteLine("Inicio email enviado event");
        System.Windows.Application.Current.Dispatcher.Invoke(() =>
        {
            Console.WriteLine("Inicio Dispatcher");

            System.Windows.Window historicoEmailCadastro = new     System.Windows.Window
            {
                Title = "Cadastro de Histórico de Email",
                Content = new HistoricoEmailCadastro(ListaPendenciaId,     PendenciaConsulta),
                Width = 270,
                Height = 260,
                ResizeMode = ResizeMode.NoResize,
                Topmost = true,
                WindowStartupLocation =    WindowStartupLocation.CenterScreen
            };

            Console.WriteLine("Criou a window");

            historicoEmailCadastro.ShowDialog();

            if (StatusId == 4)
            {
                PendenciaController pendenciaControllerEmail = new     PendenciaController();
                 pendenciaControllerEmail.PendenciaStatusAtualizarPorPendenciaId(ListaPendenciaId, StatusId, optionalData: true);
                PendenciaConsulta.PendenciaStatusAtualizarPorPendenciaId(ListaPendenciaId, StatusId, optionalData: true);
            }

            else
            {
                PendenciaController pendenciaControllerEmail = new     PendenciaController();
                pendenciaControllerEmail.PendenciaStatusAtualizarPorPendenciaId(ListaPendenciaId, StatusId);
                PendenciaConsulta.PendenciaStatusAtualizarPorPendenciaId(ListaPendenciaId, StatusId);

            }

            PendenciaConsulta.PesquisarOffLine();
        });
    }
}

The problem is that only Event is executed in the first email sent. Ex: I have two different emails, in one object "emailEnviado" the Listpendenciaid has 11 items, in the second email the list has 4 items.

When sending the email is the first or the second, the object comes with the correct properties. If I send the first email with the list of 11 objects first it comes correct and if I send the second email first it comes the list of 4 correct objects. But the event "Emailenviadoevent" is only triggered the first time I send an email and the others that are open and send after do not trigger the event.