попробуйте:
private void AvailabilityChanged(object sender, NetworkAvailabilityEventArgs e)
{
if (e.IsAvailable)
Console.WriteLine("Wi-Fi conectado " + DateTime.Now );
else
Console.WriteLine("Wi-Fi desconectado " + DateTime.Now);
}
public Inicio()
{
InitializeComponent();
NetworkAvailabilityChangedEventHandler myHandler = new NetworkAvailabilityChangedEventHandler(AvailabilityChanged);
NetworkChange.NetworkAvailabilityChanged += myHandler;
}