获取公网IP地址

/// <summary>
///GetOutIP 的摘要说明
/// </summary>
public class GetOutIP
{
private string strgetIP;

public GetOutIP()
{
//
//TODO: 在此处添加构造函数逻辑
//
netIP();
getIP();

}

public string renetIP()
{ return netIP(); }//返回网络IP

public string regetIP()
{ return strgetIP; }//返回内网IP

/// <summary>
/// 获取公网IP，获取失败时返回本地IP
/// </summary>
/// <returns></returns>
public static string netIP()
{
string s = "";
try
{
Uri uri = new Uri("http://www.ip138.com/ip2city.asp");//查本机网络IP的网页
HttpWebRequest req = (HttpWebRequest)WebRequest.Create(uri);
req.Method = "POST";
req.ContentType = "application/x-www-form-urlencoded";
req.ContentLength = 0;
req.CookieContainer = new CookieContainer();
req.GetRequestStream().Write(new byte[0], 0, 0);
HttpWebResponse res = (HttpWebResponse)(req.GetResponse());
StreamReader rs = new StreamReader(res.GetResponseStream(), Encoding.GetEncoding("GB18030"));
s = rs.ReadToEnd();
rs.Close();
req.Abort();
res.Close();
s = s.Substring(s.IndexOf('[') + 1, s.Length - s.LastIndexOf(']') - 11); //自己灵活取出IP
}
catch
{
GetOutIP gg = new GetOutIP();
s = gg.getIP();
}

return s;
}

/// <summary>
/// 获取本地IP
/// </summary>
/// <returns></returns>
public string getIP()//注意与static 的区别
{
System.Net.IPAddress[] addressList = Dns.GetHostByName(Dns.GetHostName()).AddressList;//获取本机内网IP

strgetIP = addressList[0].ToString();
return strgetIP;

}
}