Obtener la dirección IP de un ordenador

using System.Net;
 
string[] GetIPaddresses(string computername)
{
    string[] saddr = null;
    IPAddress[] addr = Dns.Resolve(computername).AddressList;
 
    if (addr.Length > 0)
    {
        saddr = new String[addr.Length];
        for (int i = 0; i < addr.Length; i++)
            saddr[i] = addr[i].ToString();   
    }
    return saddr;
}