title: How can I hide the menu of Master page until the user do login in asp.net
body: <p>I create a master page with a navigation bar. I made index page as a login page, so I use the login control in index.aspx which is registered under the master page. </p>
  
  <p>Now my question is how can I hide the navigation bar which is in master page until the user do login, after the user doing successful login the navigation bar should appear </p>