private void TabControl_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            if (e.Source is TabControl && this.IsLoaded)
            {
                TabItem selectedTab = e.AddedItems[0] as TabItem;
                if (selectedTab == null)
                {
                    return;
                }

                if (selectedTab.Name == "AddAdminTabItem")
                {
                    AddAdminFrame.Navigate(new PasswordConfirmation(LoggedAdminLogin, OnPasswordConfirmed));
                }
            }
        }
 private void OnPasswordConfirmed()
 {
     AddAdminFrame.Navigate(AddAdminTab);
 }