/// <summary>
/// 获取本机在局域网的IP地址
/// </summary>
/// <returns></returns>
private string GetLocalIPAddress()
{
    System.Net.IPAddress[] addressList = Dns.GetHostEntry(Dns.GetHostName()).AddressList;
    string strNativeIP = "";
    string strServerIP = "";
    if (addressList.Length > 1)
    {
strNativeIP = addressList[0].ToString();
strServerIP = addressList[1].ToString();
    }
    else if(addressList.Length==1)
    {
strServerIP = addressList[0].ToString();
    }
    return strServerIP;
}

/// <summary>
/// 获取本机的上网IP
/// </summary>
/// <returns></returns>
private string GetConnectNetAddress()
{
    string strUrl = "http://www.ip138.com/ip2city.asp"; //获得IP的网址
    Uri uri = new Uri(strUrl);
    WebRequest webreq = WebRequest.Create(uri);
    Stream s = webreq.GetResponse().GetResponseStream();
    StreamReader sr = new StreamReader(s, Encoding.Default);
    string all = sr.ReadToEnd(); //读取网站返回的数据 格式：您的IP地址是：[x.x.x.x]
    int i = all.IndexOf("[") + 1;
    string tempip = all.Substring(i, 15);
    string ip = tempip.Replace("]", "").Replace(" ", "").Replace("<", "");
    return ip;
}