title: How to determine if network interface is connected to the Internet (i. e. the computer is online)
body: <p>I need a way to determine internet availability programmatically.
  At now i use Ping to constantly ping some internet site.</p>
  
  <p>But it seems Windows 7 though determines internet availability in some other way.
  If computer is online there is earth icon on the network interface icon in the System Tray.</p>
  
  <p>The question is: is there any standard Win32 way to check online status, win event or something, and if so, how to use it from C#?</p>