The System.Net.NetworkInformation.NetworkChange class raises NetworkChange.NetworkAvailabilityChanged events when the availability of the network changes. The network is available when at least one network interface is marked "up" and is not a tunnel or loopback interface.

To have a System.Net.NetworkInformation.NetworkChange object call an event-handling method when a NetworkChange.NetworkAvailabilityChanged event occurs, you must associate the method with a System.Net.NetworkInformation.NetworkAvailabilityChangedEventHandler delegate, and add this delegate to this event.

The NetworkChange.NetworkAvailabilityChanged event is supported on Windows 2000 and later.