Detect network connectivity from a WPF/XBAP Application?

Question

Is there any way to determine if an XBAP (WPF hosted in a browser) application has network connectivity? If not, how would a traditional windows client written in C# and .NET determine if it has connectivity?

Basically the use case is an XBAP application running on a mobile laptop connected to an intranet via WiFi. The laptop will not have a connection to the Internet. The WiFi connection may or may not be there depending upon where the user is at the time.

Receipt

Try this code it is working for me. #520847 – Electret

#520847 – Electret

Answer 1

GateWayIPAddressInformation should work: http://msdn.microsoft.com/en-us/library/system.net.networkinformation.gatewayipaddressinformation(loband).aspx

If you get the gateway IP address, and you can Ping (http://msdn.microsoft.com/en-us/library/system.net.networkinformation.ping(loband).aspx) it you are probably connected.

Dolhenty

Answer 2

Do this in your InitializeComponent():

// Add EventHandler for NetworkAddressChanged event    
NetworkChange.NetworkAddressChanged += new NetworkAddressChangedEventHandler(AddressChangedCallback);

Here is the Method that is called when that event fires:

internal void AddressChangedCallback(object sender, EventArgs e)
{
    // Check for NetworkConnectivity
    _isInternetConnectionActive = new NetworkConnectivity().IsInternetConnected; 
}

Here is the NetworkConnectivity Class:

public class NetworkConnectivity
{
    private List<IPAddress> _ipAddresses = new List<IPAddress>();

    public NetworkConnectivity()
    {
        _ipAddresses = new List<IPAddress>();
    }

    #region Public Properties
    public int CountIPAddresses
    {
        get { return this.IPAddresses.Count; }
    }
    public List<IPAddress> IPAddresses
    {
        get
        {
            _ipAddresses.Clear();
            // Get a listing of all network adapters
            NetworkInterface[] adapters = NetworkInterface.GetAllNetworkInterfaces();
            foreach (NetworkInterface adapter in adapters)
            {
                IPInterfaceProperties adapterProperties = adapter.GetIPProperties();
                GatewayIPAddressInformationCollection addresses = adapterProperties.GatewayAddresses;
                // If this adapter has at least 1 IPAddress
                if (addresses.Count > 0)
                {
                    // Loop through all IP Addresses
                    foreach (GatewayIPAddressInformation address in addresses)
                    {
                        _ipAddresses.Add(address.Address);
                    }
                }
            } 
            return _ipAddresses;
        }
    }
    public bool IsInternetConnected
    {
        get
        {
            if (this.CountIPAddresses == 0)
            {
                return false;
            }
            else
            {
                //IPAddress[] ips = ResolveDNSAddress("google.com");
                //return PingIPAddressPool(ips);
                return PingIPAddress("72.14.204.104"); // Google IP
            }
        }
    }
    #endregion

    #region Public Methods
    public IPAddress[] ResolveDNSAddress(string UrlAddress)
    {
        IPHostEntry hostInfo = Dns.Resolve(UrlAddress);
        return hostInfo.AddressList;
    }
    public bool PingIPAddressPool(IPAddress[] ipAddresses)
    {
        foreach (IPAddress ip in ipAddresses)
        {
            if (PingIPAddress(ip.Address.ToString()))
            {
                return true;
            }
        }
        return false;
    }
    public bool PingIPAddress(string ip)
    {
        // Pinging
        IPAddress addr = IPAddress.Parse(ip);
        Ping pingSender = new Ping();
        PingOptions options = new PingOptions();

        // Use the default Ttl value which is 128,
        // but change the fragmentation behavior.
        options.DontFragment = true;

        // Create a buffer of 32 bytes of data to be transmitted.
        string data = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
        byte[] buffer = Encoding.ASCII.GetBytes(data);
        int timeout = 15; // seconds to wait for response
        int attempts = 2; // ping attempts
        for (int i = 0; i < attempts; i++)
        {
            PingReply reply = pingSender.Send(addr, timeout, buffer, options); 
            if (reply.Status == IPStatus.Success)
            { return true; }
        }
        return false;
    }
    #endregion

}

Medeiros

this code is good, but some functions like Dns.Resolve() are obsoleted. – Biddy