檢查網絡是否正常

 private void CheckNetStatus()
        {
            string ip = tbIP.Text.Trim();
            Ping p = new Ping();//創建Ping對象p
            PingReply pr = p.Send(ip);//向指定IP或者主機名的計算機發送ICMP協議的ping數據包

            if (pr.Status == IPStatus.Success)//如果ping成功
            {
                MessageBox.Show("網絡連接成功, 執行下面任務...");
            }
            else
            {
                int times = 0;//重新連接次數;
                do
                {
                    if (times >= 12)
                    {
                        MessageBox.Show("重新嘗試連接超過12次,連接失敗程序結束");
                        return;
                    }

                    Thread.Sleep(2000);//等待十分鐘(方便測試的話，你可以改爲1000)
                    pr = p.Send(ip);

                    MessageBox.Show(pr.Status.ToString());

                    times++;

                }
                while (pr.Status != IPStatus.Success);

                MessageBox.Show("連接成功");
                times = 0;//連接成功，重新連接次數清爲0;
            }
        }