Share via

NetworkChange Class


Allows applications to receive notification when the Internet Protocol (IP) address of a network interface, also called a network card or adapter, changes.

public ref class NetworkChange abstract sealed
public ref class NetworkChange
public ref class NetworkChange sealed
public static class NetworkChange
public class NetworkChange
public sealed class NetworkChange
type NetworkChange = class
Public Class NetworkChange
Public NotInheritable Class NetworkChange


The following code example listens for address changes and displays the status of network interfaces when a NetworkAddressChanged event occurs.

#using <System.dll>

using namespace System;
using namespace System::Net;
using namespace System::Net::NetworkInformation;
void AddressChangedCallback( Object^ /*sender*/, EventArgs^ /*e*/ )
   array<NetworkInterface^>^adapters = NetworkInterface::GetAllNetworkInterfaces();
   System::Collections::IEnumerator^ myEnum = adapters->GetEnumerator();
   while ( myEnum->MoveNext() )
      NetworkInterface^ n = safe_cast<NetworkInterface^>(myEnum->Current);
      Console::WriteLine( "   {0} is {1}", n->Name, n->OperationalStatus );

int main()
   NetworkChange::NetworkAddressChanged += gcnew NetworkAddressChangedEventHandler( AddressChangedCallback );
   Console::WriteLine( "Listening for address changes. Press any key to exit." );
using System;
using System.Net;
using System.Net.NetworkInformation;

namespace Examples.Net.AddressChanges
    public class NetworkingExample
        public static void Main()
            NetworkChange.NetworkAddressChanged += new
            Console.WriteLine("Listening for address changes. Press any key to exit.");
        static void AddressChangedCallback(object sender, EventArgs e)

            NetworkInterface[] adapters = NetworkInterface.GetAllNetworkInterfaces();
            foreach(NetworkInterface n in adapters)
                Console.WriteLine("   {0} is {1}", n.Name, n.OperationalStatus);
Imports System.Net
Imports System.Net.NetworkInformation

Public Class NetworkingExample
    Public Shared Sub Main()
        AddHandler NetworkChange.NetworkAddressChanged, AddressOf AddressChangedCallback
        Console.WriteLine("Listening for address changes. Press any key to exit.")
    End Sub
    Private Shared Sub AddressChangedCallback(ByVal sender As Object, ByVal e As EventArgs)

        Dim adapters As NetworkInterface() = NetworkInterface.GetAllNetworkInterfaces()
        Dim n As NetworkInterface
        For Each n In adapters
            Console.WriteLine("   {0} is {1}", n.Name, n.OperationalStatus)
        Next n
    End Sub
End Class


The NetworkChange class provides address change notification by raising NetworkAddressChanged events. An interface address can change for many reasons, such as a disconnected network cable, moving out of range of a wireless Local Area Network, or hardware failure.

To receive notification, you must identify your application's event handlers, which are one or more methods that perform your application-specific tasks each time the event is raised. To have a NetworkChange object call your event-handling methods when a NetworkAddressChanged event occurs, you must associate the methods with a NetworkAddressChangedEventHandler delegate, and add this delegate to the event.



Initializes a new instance of the NetworkChange class.



Registers a network change instance to receive network change events.



Occurs when the IP address of a network interface changes.


Occurs when the availability of the network changes.

Applies to