Query Local IP Address

After much digging, I found the information you need using NetworkInformation and HostName.

NetworkInformation.GetInternetConnectionProfile retrieves the connection profile associated with the internet connection currently used by the local machine.

NetworkInformation.GetHostNames retrieves a list of host names. It’s not obvious but this includes IPv4 and IPv6 addresses as strings.

Using this information we can get the IP address of the network adapter connected to the internet like this:

public string CurrentIPAddress()
{
    var icp = NetworkInformation.GetInternetConnectionProfile();

    if (icp != null && icp.NetworkAdapter != null)
    {
        var hostname =
            NetworkInformation.GetHostNames()
                .SingleOrDefault(
                    hn =>
                    hn.IPInformation != null && hn.IPInformation.NetworkAdapter != null
                    && hn.IPInformation.NetworkAdapter.NetworkAdapterId
                    == icp.NetworkAdapter.NetworkAdapterId);

        if (hostname != null)
        {
            // the ip address
            return hostname.CanonicalName;
        }
    }

    return string.Empty;
}

Note that HostName has properties CanonicalName, DisplayName and RawName, but they all seem to return the same string.

We can also get addresses for multiple adapters with code similar to this:

private IEnumerable<string> GetCurrentIpAddresses()
{
    var profiles = NetworkInformation.GetConnectionProfiles().ToList();

    // the Internet connection profile doesn't seem to be in the above list
    profiles.Add(NetworkInformation.GetInternetConnectionProfile());

    IEnumerable<HostName> hostnames =
        NetworkInformation.GetHostNames().Where(h => 
            h.IPInformation != null &&
            h.IPInformation.NetworkAdapter != null).ToList();

    return (from h in hostnames
            from p in profiles
            where h.IPInformation.NetworkAdapter.NetworkAdapterId ==
                  p.NetworkAdapter.NetworkAdapterId
            select string.Format("{0}, {1}", p.ProfileName, h.CanonicalName)).ToList();
}