如何检查是否TcpClient的连接被关闭？ [英] How to check if TcpClient Connection is closed?

问题描述

我用TcpClient的玩弄，我试图找出如何使连接属性说假的，当连接断开。

I'm playing around with the TcpClient and I'm trying to figure out how to make the Connected property say false when a connection is dropped.

我试图做

NetworkStream ns = client.GetStream();
ns.Write(new byte[1], 0, 0);

但它仍然不会显示我，如果TcpClient的断开。你会如何​​去这个使用TcpClient的？

But it still will not show me if the TcpClient is disconnected. How would you go about this using a TcpClient?

推荐答案

我不建议你尝试写只是为了测试插座。不要对.NET的Connected属性接力无论是。

I wouldn't recommend you to try write just for testing the socket. And don't relay on .NET's Connected property either.

如果你想知道，如果远程端点仍处于活动状态，您可以使用TcpConnectionInformation：

If you want to know if the remote end point is still active, you can use TcpConnectionInformation:

TcpClient client = new TcpClient(host, port);

IPGlobalProperties ipProperties = IPGlobalProperties.GetIPGlobalProperties();
TcpConnectionInformation[] tcpConnections = ipProperties.GetActiveTcpConnections().Where(x => x.LocalEndPoint.Equals(client.Client.LocalEndPoint) && x.RemoteEndPoint.Equals(client.Client.RemoteEndPoint)).ToArray();

if (tcpConnections != null && tcpConnections.Length > 0)
{
    TcpState stateOfConnection = tcpConnections.First().State;
    if (stateOfConnection == TcpState.Established)
    {
        // Connection is OK
    }
    else 
    {
        // No active tcp Connection to hostName:port
    }

}
client.Close();

另请参见：

<一href=\"http://msdn.microsoft.com/en-us/library/system.net.networkinformation.tcpconnectioninformation%28v=vs.110%29.aspx\">TcpConnectionInformation MSDN上

<一href=\"http://msdn.microsoft.com/en-us/library/system.net.networkinformation.ipglobalproperties.aspx\">IPGlobalProperties 的MSDN上

说明<一href=\"http://msdn.microsoft.com/en-us/library/system.net.networkinformation.tcpstate%28v=vs.110%29.aspx\">TcpState美国

上的Netstat 维基百科

See Also:
TcpConnectionInformation on MSDN
IPGlobalProperties on MSDN
Description of TcpState states
Netstat on Wikipedia

和这里是作为TcpClient的扩展方法。

And here it is as an extension method on TcpClient.

public static TcpState GetState(this TcpClient tcpClient)
{
  var foo = IPGlobalProperties.GetIPGlobalProperties()
    .GetActiveTcpConnections()
    .SingleOrDefault(x => x.LocalEndPoint.Equals(tcpClient.Client.LocalEndPoint));
  return foo != null ? foo.State : TcpState.Unknown;
}

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