內網
 IPAddress ipAddr = Dns.Resolve(Dns.GetHostName()).AddressList[0];//獲得當前IP地址
            string ip = ipAddr.ToString();

外網

 //獲取本機的公網IP
        public static string GetPublicNetworkIP()
        {
            string tempip = "";
            WebRequest request = WebRequest.Create("http://ip.qq.com");
            request.Timeout 
 
= 10000;
            WebResponse response = request.GetResponse();
            Stream resStream = response.GetResponseStream();
            StreamReader sr = new StreamReader(resStream, System.Text.Encoding.Default);
            string htmlinfo = sr.ReadToEnd();
            //匹配IP的正則表達式
            Regex r = new
 
 Regex("((25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]\\d|\\d)\\.){3}(25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]\\d|[1-9])", RegexOptions.None);
            Match mc = r.Match(htmlinfo);
            //獲取匹配到的IP
            tempip = mc.Groups[0].Value;
            resStream.Close();
            sr.Close();
            return tempip;
        }
 

c#得到本機內網ip、外網ip