title: How can I create a login page in Xamarin.Forms?
body: <p>How can I create a login page using <code>Xamarin.Forms</code>?</p>
  
  <p>I'm debugging on Android device and<br>
  on the page I try to query the given username and password from an MSSQL database in MSSQL</p>
  
  <p>and if the login be successful, the page will navigate to a new page, else will show authentication failed.</p>
  
  <p>How can I do this in Xamarin.Forms?</p>