//设置对外访问所使用网卡的IPstring sendingIp = "192.168.0.1";//设置对外访问所使用的端口int sendingPort = 5000;Uri uri = new Uri("http://google.com");HttpWebRequest wr = (HttpWebRequest)WebRequest.Create(uri);//获取对外访问的包，并指定使用那个IP（网卡）与端口来发送数据包ServicePoint sp = ServicePointManager.FindServicePoint(uri);sp.BindIPEndPointDelegate =    (servicePoint,remoteEp,retryCount) =>         {             return new IPEndPoint(IPAddress.Parse(sendingIp),sendingPort);         };//提交请求并获取返回结果var data = new StreamReader(wr.GetResponse().GetResponseStream()).ReadToEnd();

//获取多网卡Ip NetworkInterface[] NetworkInterfaces = NetworkInterface.GetAllNetworkInterfaces();            foreach (NetworkInterface NetworkIntf in NetworkInterfaces)            {                IPInterfaceProperties IPInterfaceProperties = NetworkIntf.GetIPProperties();                UnicastIPAddressInformationCollection UnicastIPAddressInformationCollection = IPInterfaceProperties.UnicastAddresses;                foreach (UnicastIPAddressInformation UnicastIPAddressInformation in UnicastIPAddressInformationCollection)                {                    if (UnicastIPAddressInformation.Address.AddressFamily == AddressFamily.InterNetwork)                    {                        MessageBox.Show(UnicastIPAddressInformation.Address.ToString());                    }                }            }