不断检查互联网连接

如何在我的应用程序中不断检查互联网连接，如果连接不可用则进行响应？

目前我正在使用：

while(true) { if(HasConnection()) { //doSomething.. } //stop app by 1sec } 

但它似乎相当不优雅。

Answer 1

超级用户对此问题的接受答案描述了Windows确定其是否具有网络访问权限的方式。 您可以使用类似的方法，但是当您的应用程序启动时，我会生成一个单独的线程负责进行检查。 让单独的线程以您认为最好的方式执行检查，并在连接状态更改时引发事件。

Answer 2

您正在寻找NetworkAvailabilityChanged事件 。

要检查互联网连接，您可以ping一个可靠的网站，例如Google.com。

请注意，无法通知互联网连接的每次更改（例如ISP中断）。

Answer 3

使用以下代码：

 public static class LocalSystemConnection { [DllImport("wininet.dll", SetLastError=true, CallingConvention = CallingConvention.ThisCall)] extern static bool InternetGetConnectedState(out ConnectionStates lpdwFlags, long dwReserved); /// 
 /// Retrieves the connected state of the local system. /// 
 /// A  value that receives the connection description. ///  /// A return value of true indicates that either the modem connection is active, or a LAN connection is active and a proxy is properly configured for the LAN. /// A return value of false indicates that neither the modem nor the LAN is connected. /// If false is returned, the  flag may be set to indicate that autodial is configured to "always dial" but is not currently active. /// If autodial is not configured, the function returns false. ///  public static bool IsConnectedToInternet(out ConnectionStates connectionStates) { connectionStates = ConnectionStates.Unknown; return InternetGetConnectedState(out connectionStates, 0); } /// 
 /// Retrieves the connected state of the local system. /// 
 ///  /// A return value of true indicates that either the modem connection is active, or a LAN connection is active and a proxy is properly configured for the LAN. /// A return value of false indicates that neither the modem nor the LAN is connected. /// If false is returned, the  flag may be set to indicate that autodial is configured to "always dial" but is not currently active. /// If autodial is not configured, the function returns false. ///  public static bool IsConnectedToInternet() { ConnectionStates state = ConnectionStates.Unknown; return IsConnectedToInternet(out state); } } [Flags] public enum ConnectionStates { /// 
 /// Unknown state. /// 
 Unknown = 0, /// 
 /// Local system uses a modem to connect to the Internet. /// 
 Modem = 0x1, /// 
 /// Local system uses a local area network to connect to the Internet. /// 
 LAN = 0x2, /// 
 /// Local system uses a proxy server to connect to the Internet. /// 
 Proxy = 0x4, /// 
 /// Local system has RAS (Remote Access Services) installed. /// 
 RasInstalled = 0x10, /// 
 /// Local system is in offline mode. /// 
 Offline = 0x20, /// 
 /// Local system has a valid connection to the Internet, but it might or might not be currently connected. /// 
 Configured = 0x40, } 

Answer 4

如果您只需要知道是否有至少一个连接可用，您可以尝试这样做：

InternetGetConnectedStateEx（）

http://msdn.microsoft.com/en-us/library/aa384705%28v=vs.85%29.aspx

Answer 5

你怎么知道你是否有互联网连接？ 您是否可以将数据包路由到附近的路由器？ 也许机器只有一个网卡，一个网关，也许网关的连接断电但机器仍然可以路由到网关和本地网络？

也许这台机器有一个网卡和十几个网关; 也许他们总是来去匆匆，但其中一个总是在起来？

如果机器有多个NIC但只有一个网关怎么办？ 也许它可以路由到互联网的某个子集，但仍然可以很好地连接到未连接到互联网的本地网络？

如果机器有多个网卡，多个网关，但出于管理政策的原因，仍然只有部分互联网是可路由的，该怎么办？

您是否真的只关心客户是否与您的服务器连接？

数据包之间可以接受什么样的延迟？ （30ms是好的，300ms正在推动人类耐力的极限，3000ms是无法忍受的长时间，960000ms是连接太阳探测器所需要的。）什么样的丢包是可以接受的？

你真的想测量什么？

Answer 6

这将是一个开始，但正如sarnold所提到的，你需要考虑很多事情

Answer 7

您可以通过ping某些网站测试互联网连接，例如：

  public bool IsConnectedToInternet { try { using (System.Net.NetworkInformation.Ping ping = new System.Net.NetworkInformation.Ping()) { string address = @"http://www.google.com";// System.Net.NetworkInformation.PingReply pingReplay = ping.Send(address);//you can specify timeout. if (pingReplay.Status == System.Net.NetworkInformation.IPStatus.Success) { return true; } } } catch { #if DEBUG System.Diagnostics.Debugger.Break(); #endif//DEBUG } return false; } 

Answer 8

如果你想连续检查然后使用计时器

  private Timer timer1; public void InitTimer() { timer1 = new Timer(); timer1.Tick += new EventHandler(timerEvent); timer1.Interval = 2000; // in miliseconds timer1.Start(); } private void timerEvent(object sender, EventArgs e) { DoSomeThingWithInternet(); } private void DoSomeThingWithInternet() { if (isConnected()) { // inform user that "you're connected to internet" } else { // inform user that "you're not connected to internet" } } public static bool isConnected() { try { using (var client = new WebClient()) using (client.OpenRead("http://clients3.google.com/generate_204")) { return true; } } catch { return false; } }