(转)判断计算机是否有网络链接

原文：http://topic.csdn.net/u/20081223/00/27301898-6c7c-4e4a-a70d-d4ac7f00886b.html

 //先通过.Net提供的类库判断似乎否有网络连接
        public static bool IsAnyNetworkAvailable()
        {
            try
            {
                foreach (NetworkInterface ni in NetworkInterface.GetAllNetworkInterfaces())
                {
                    if (ni.OperationalStatus == OperationalStatus.Up &&
                        ni.NetworkInterfaceType != NetworkInterfaceType.Loopback &&
                        ni.NetworkInterfaceType != NetworkInterfaceType.Tunnel)
                    {
                        IPInterfaceProperties iip = ni.GetIPProperties();
                        if (iip != null && iip.UnicastAddresses != null && iip.UnicastAddresses.Count > 0)
                        {
                            return true;
                        }
                    }
                }
                return false;
            }
            catch
            {
                //如果有异常,直接调用API判断
                return IsInternetConnected();
            }
        }

        [DllImport("wininet.dll")]
        private static extern bool InternetGetConnectedState(out int connectionDescription, int reservedValue);

        public static bool IsInternetConnected()
        {
            int i;
            return InternetGetConnectedState(out i, 0);
        }

 

没测试，留作备用的