利用.Net 的 System.Net.NetworkInformation.Ping 測試網路是否正常！

System.Net.NetworkInformation.Ping NetPing = new System.Net.NetworkInformation.Ping();
System.Net.NetworkInformation.PingReply NetPingReply = NetPing.Send("168.95.1.1", 5000);

if(NetPingReply.Status == System.Net.NetworkInformation.IPStatus.Success)
{
     MessageBox.Show("OK");
}
else
{
     MessageBox.Show("ERROR");
}