protected override void OnNavigatedTo(NavigationEventArgs e)
 {
     ArrayList arrayList = e.Parameter as ArrayList;
     principalPage = arrayList[0] as IPrincipalPage;
     string nombreMascota= arrayList[1] as string;
     textMensaje.Text = "Esta seguro que deseas eliminar la mascota "+nombreMascota+"?";
 }
 protected override void OnNavigatedTo(NavigationEventArgs e)
 {
     ArrayList arrayList = e.Parameter as ArrayList;
     principalPage = arrayList[0] as IPrincipalPage;
     tipomascota =arrayList[1] as string;                 
     titulo.Text = "Agregar "+tipomascota;
     if(tipomascota.Equals("Adultos"))
     {
         textEdad.Text = "AƱos";
     }
     else
     {
         textEdad.Text = "Meses";
     }
 }