Get the local ip address of the principal network adapter card.

GetLocalIpAddress.cs

public string getLocalIPAddress()
{
    IPHostEntry host;
    string localIP = "";
    host = Dns.GetHostEntry(Dns.GetHostName());
    foreach (IPAddress ip in host.AddressList)
    {
        if (ip.AddressFamily == AddressFamily.InterNetwork)
        {
            localIP = ip.ToString();
            break;
        }
    }
    return localIP;
}