基于Tast定时检测网络本地网络状况

首先我们需要使用winInet.dll中的InternetGetConnectedState方法来检测本地是否连接网络，然后再通过ping的方式来获取网络状况。

然后我们采用Task来开辟一个线程来定时检测网络状况，最后自定义一个委托，然后用事件来简单的通知网络状况。

具体代码如下：

   public class NetWorkHelper
    {
       /// <summary>
       /// 委托
       /// </summary>
       /// <param name="flag"></param>
       /// <param name="msg"></param>
       public delegate void NetStatusDelegate(bool flag, string msg);
       public event NetStatusDelegate NetStatusEvent;
        public void StartCheck()
        {
            List<string> urlls = new List<string>() { "www.baidu.com", "www.sina.com", "www.cnblogs.com", "www.163.com", "www.csdn.com" };
            Task.Run(async () =>
            {
                await Task.Run(() =>
                {
                    while (true)
                    {
                        try
                        {
                            CheckServeStatus(urlls);
                        }
                        catch (Exception ex)
                        {
                            if (NetStatusEvent!=null)
                            {
                                NetStatusEvent(false, "网络异常");
                            }
                        }
                        finally
                        {
                            System.Threading.Thread.Sleep(3000);
                        }
                    }
                });
            });
        }
        // <summary>
        /// 检测网络连接状态
        /// </summary>
        /// <param name="urls"></param>
        public  void CheckServeStatus(List<string> urls)
        {
            int errCount = 0;//ping时连接失败个数

            if (!LocalConnectionStatus())
            {
                if (NetStatusEvent != null)
                {
                    NetStatusEvent(false, "网络异常--->无连接");
                }
            }
            else if (!MyPing(urls, out errCount))
            {
                if ((double)errCount / urls.Count >= 0.3)
                {
                    if (NetStatusEvent != null)
                    {
                        NetStatusEvent(false, "网络异常--->连接多次无响应");
                    }
                   
                }
                else
                {
                    if (NetStatusEvent != null)
                    {
                        NetStatusEvent(false, "网络异常--->网络不稳定");
                    }
                   
                }
            }
            else
            {
                if (NetStatusEvent != null)
                {
                    NetStatusEvent(false, "网络正常");
                }
            }
        }
        private const int INTERNET_CONNECTION_MODEM = 1;
        private const int INTERNET_CONNECTION_LAN = 2;

        [System.Runtime.InteropServices.DllImport("winInet.dll")]
        private static extern bool InternetGetConnectedState(ref int dwFlag, int dwReserved);

        /// <summary>
        /// 判断本地的连接状态
        /// </summary>
        /// <returns></returns>
        private static bool LocalConnectionStatus()
        {
            try
            {
                System.Int32 dwFlag = new Int32();
                if (!InternetGetConnectedState(ref dwFlag, 0))
                {
                    Console.WriteLine("LocalConnectionStatus--未连网!");
                    return false;
                }
                else
                {
                    if ((dwFlag & INTERNET_CONNECTION_MODEM) != 0)
                    {
                        Console.WriteLine("LocalConnectionStatus--采用调制解调器上网。");
                        return true;
                    }
                    else if ((dwFlag & INTERNET_CONNECTION_LAN) != 0)
                    {
                        Console.WriteLine("LocalConnectionStatus--采用网卡上网。");
                        return true;
                    }
                }
            }
            catch (Exception ex)
            {
                
              
            }
            return false;
        }
        /// <summary>
        /// Ping命令检测网络是否畅通
        /// </summary>
        /// <param name="urls">URL数据</param>
        /// <param name="errorCount">ping时连接失败个数</param>
        /// <returns></returns>
        public static bool MyPing(List<string> urls, out int errorCount)
        {
            try
            {
                bool isconn = true;
                Ping ping = new Ping();
                errorCount = 0;
                try
                {
                    PingReply pr;
                    for (int i = 0; i < urls.Count; i++)
                    {
                        pr = ping.Send(urls[i]);
                        if (pr.Status != IPStatus.Success)
                        {
                            isconn = false;
                            errorCount++;
                        }
                    }
                }
                catch
                {
                    isconn = false;
                    errorCount = urls.Count;
                }
                return isconn;
            }
            catch (Exception ex)
            {
                throw new Exception(ex.ToString());
            }
        }

    }