Change Hamburger menu (master) after user logs in

Hi,

I am trying to change my hamburger menu in my MasterDetailPage after the user logs in but with no luck.

Here is what I tried so far:

1) I tried the MessagingCenter example advised here: /discussion/66945/xamarin-forms-navigation-login-masterdetailpage-logout-flow-handling

but the app freezes.

2) Tried the accepted answer in /discussion/94209/xamarin-forms-change-page-after-login-properly

but the app freezes.

I tried to change the new Master ( a different hamburger menu) after the user logs in ( in a ContentPage which is Detail).

3) I created a method in the MenuPage (master) to change the component properties

  public void showloggedinlayout()
    {



        if (ProfilPage.loggedin)
        {

            ucet_stack.IsVisible = true;
            ucet.IsVisible = true;
            ucet.Text = "Váš účet " + ProfilPage.meno;
        }
        else
        {
            ucet_stack.IsVisible = false;
            ucet.IsVisible = false;

        }

    }

I call the method like:

     MenuPage p = new MenuPage();
     p. showloggedinlayout();

it fires but the components never become visible like the code supposed to make them visible.

Any other ways to dynamically change the hamburger menu after the user logs in?