C# TcpClient如何监测网络连接状态

[studyarea]

在网上搜了好久都没有找到合适的办法，网上的方法都只是检测到一端Tcp程序关掉之后的情况，而对于拔网线之类的都没有很好的决定方法。求大神们指导！！！

[欢乐的小猪]

cmd，ping ip

 Process p = new Process();
            p.StartInfo.FileName = "cmd.exe";
            // 调用的是 CMD.EXE
            p.StartInfo.UseShellExecute = false;
            p.StartInfo.RedirectStandardInput = true;
            p.StartInfo.RedirectStandardOutput = true;
            p.StartInfo.RedirectStandardError = true;
            p.StartInfo.CreateNoWindow = true;

            p.Start();
            Console.Write("Try to ping " + Paras[1] + "("+Paras[Paras.Count()-1] +")"+ "\r\n");
            p.StandardInput.WriteLine("ping -n 1 " + Paras[1]);
            // ping –n 1 IP
            p.StandardInput.WriteLine("exit");
            string strRst = p.StandardOutput.ReadToEnd();
            p.Close();
            //取得输出结果
            string result;
            if (strRst.IndexOf("(0% loss)") != -1 || (strRst.IndexOf("(0% 丢失)") != -1 && (strRst.IndexOf("无法访问目标主机") == -1)))
                result = "网络正常";
            else
            {
                result =  "网络异常，请检查网络情况！";
            }
          
            return result;

[linjiagao052]

public struct OVERLAPPED
        {
            public IntPtr Internal;
            public IntPtr InternalHigh;

            public IntPtr Pointer;

            public IntPtr hEvent;
        };

        [DllImport("Iphlpapi.dll")]
        public extern static uint NotifyAddrChange(ref IntPtr handle, ref OVERLAPPED overlapped);

        [DllImport("Ws2_32.dll")]
        public extern static IntPtr WSACreateEvent();

        [DllImport("Ws2_32.dll")]
        public extern static int WSAGetLastError();

        [DllImport("Kernel32.dll")]
        public static extern int WaitForSingleObject(IntPtr hHandle, int dwMilliseconds);

        void GetAddrChangeEvent()
        {
            OVERLAPPED overlapped = new OVERLAPPED();

            IntPtr hand = IntPtr.Zero;

            overlapped.hEvent = WSACreateEvent();


            uint ret = NotifyAddrChange(ref hand, ref overlapped);

            if (0 != ret)
            {
                if (997L != WSAGetLastError())
                {
                    // some error!
                    return;
                }
            }


            if (WaitForSingleObject(overlapped.hEvent, (int)-1) == 0)
            {
                // addr change
                // MessageBox.Show("some changed!");
            }
        }


        private void button1_Click(object sender, EventArgs e)
        {
            Thread thread = new Thread(GetAddrChangeEvent);
            thread.Start();
        }

[我是飞云]

http://blog.csdn.net/educast/article/details/7430267

[studyarea]

引用 1 楼 hbu_pig 的回复:

cmd，ping ip

 Process p = new Process();
            p.StartInfo.FileName = "cmd.exe";
            // 调用的是 CMD.EXE
            p.StartInfo.UseShellExecute = false;
            p.StartInfo.RedirectStandardInput = true;
            p.StartInfo.RedirectStandardOutput = true;
            p.StartInfo.RedirectStandardError = true;
            p.StartInfo.CreateNoWindow = true;

            p.Start();
            Console.Write("Try to ping " + Paras[1] + "("+Paras[Paras.Count()-1] +")"+ "\r\n");
            p.StandardInput.WriteLine("ping -n 1 " + Paras[1]);
            // ping –n 1 IP
            p.StandardInput.WriteLine("exit");
            string strRst = p.StandardOutput.ReadToEnd();
            p.Close();
            //取得输出结果
            string result;
            if (strRst.IndexOf("(0% loss)") != -1 || (strRst.IndexOf("(0% 丢失)") != -1 && (strRst.IndexOf("无法访问目标主机") == -1)))
                result = "网络正常";
            else
            {
                result =  "网络异常，请检查网络情况！";
            }
          
            return result;

谢谢

[studyarea]

引用 2 楼 linjiagao052 的回复:

public struct OVERLAPPED
        {
            public IntPtr Internal;
            public IntPtr InternalHigh;

            public IntPtr Pointer;

            public IntPtr hEvent;
        };

        [DllImport("Iphlpapi.dll")]
        public extern static uint NotifyAddrChange(ref IntPtr handle, ref OVERLAPPED overlapped);

        [DllImport("Ws2_32.dll")]
        public extern static IntPtr WSACreateEvent();

        [DllImport("Ws2_32.dll")]
        public extern static int WSAGetLastError();

        [DllImport("Kernel32.dll")]
        public static extern int WaitForSingleObject(IntPtr hHandle, int dwMilliseconds);

        void GetAddrChangeEvent()
        {
            OVERLAPPED overlapped = new OVERLAPPED();

            IntPtr hand = IntPtr.Zero;

            overlapped.hEvent = WSACreateEvent();


            uint ret = NotifyAddrChange(ref hand, ref overlapped);

            if (0 != ret)
            {
                if (997L != WSAGetLastError())
                {
                    // some error!
                    return;
                }
            }


            if (WaitForSingleObject(overlapped.hEvent, (int)-1) == 0)
            {
                // addr change
                // MessageBox.Show("some changed!");
            }
        }


        private void button1_Click(object sender, EventArgs e)
        {
            Thread thread = new Thread(GetAddrChangeEvent);
            thread.Start();
        }

没看懂，能给的注释吗？