擷取使用者電腦的上網IP地址

           在項目中經常要擷取使用者的上網的IP地址，如何擷取使用者的IP地址，方法很多，現在介紹以下2種。

/// <summary>
        /// 擷取本機在區域網路的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;
        }

另外一種就是抓取網頁中查詢到的上網地址的IP來實現的。實現如下：

/// <summary>
        /// 擷取原生上網IP
        /// </summary>
        /// <returns></returns>
        private string GetConnectNetAddress()
        {
            string strUrl = "http://www.ip138.com/ip2city.asp"; //獲得IP的網址
            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(); //讀取網站返回的資料 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;
        }