How to check if someone is a user?
<p>I'm designing a website (ASP.NET, c#), in which you can see the controls, but you can only use them after you've logged in (for example, you can see a list of games, but you can only place a bet after you've logged in, so if you try to place a bet when you are not logged in, the site should redirect you to the login page).</p>

<p>All said, my problem is this: How can you tell, if a certain user is logged in, BEFORE he types in his credentials?</p>

<p>He his not a user yet right? For me he is just someone that is browsing my website.</p>
