C#SocketException不会被捕获 [英] C# SocketException doesn't get caught

问题描述

我的代码中出现了一个非常奇怪的现象.我正在开发一个c#聊天客户端-服务器应用程序.当我关闭服务器时，我希望客户端自动关闭.客户端正在使用StremReader从TcpClient对象读取.客户端处于while循环中，在该循环中，它读取一行(StreamReader.ReadLine())，然后对其读取的行进行一些操作.当服务器关闭时，我还关闭了服务器端的tcp连接.因此，我希望客户端看到由readline引起的SocketException，将其捕获并退出.但是，异常不会被捕获！这是客户端循环代码:

i have a really weird sitation going on in my code. I'm developping a c# chat client-server application. When i close the server i want the client to be automatically closed. The client is reading from the TcpClient object using a StremReader. The client is in a while loop where it reads a line(StreamReader.ReadLine()) and then doing some operations with the line it reads. When the serever gets closed, i also close the tcp connection server-side. So, i'm expecting the client to see a SocketException caused by the readline, catch it and exit. But the exception doesn't get caught! Here's the client loop code:

 while (true)
 {
     try
     {
          ricev = read.ReadLine();
     }
     catch(SocketException exc)
     {
         //It never gets in here
     }
     chat.Invoke(showMessage, ricev);
 }

当我关闭服务器时，Visual Studio告诉我System.dll中出现了"System.Net.Sockets.SocketException"第一次机会异常，但是我无法捕获它.为什么会这样呢?我还尝试使用

When i close the server, visual studio tells me that a "System.Net.Sockets.SocketException" first-chance exception was raised in System.dll, but i cannot catch it. Why does that happen? i also tried to catch any generic exception with a

catch
{
}

阻止，但这也不起作用.

block, but that doesn't work either.

任何帮助将不胜感激！

再尝试了几次之后，我实际上发现SocketException根本没有引发.就像我在评论中所说的那样，这真是太奇怪了，在相反的情况下，当客户端在服务器之前关闭时，就会引发异常，并且我可以取消它.我真的不知道发生了什么....

after trying some more times, i actually found out that SocketException doesn't get raised at all. That's so weird, as i said in a comment, in the opposite situation, when the client gets closed before the server, the exception gets raised and i can canth it. I don't really know what's going on....

推荐答案

如果我很了解您的情况，则是您在 TcpListener 对象" _server.Stop()"，当在​​流上调用 Read 时，它不会在客户端抛出 SocketException ...我不知道为什么这正在发生，但是我有工作要做.通过访问 TcpListener 上的基础 Socket 并在其上调用 Shutdown :

If I understand you well the scenario is when you call Stop method at TcpListener object "_server.Stop()", it will not throw SocketException at the client side when call Read on the stream... I don't know why this is happening but I have a work ground around it. it is by accessing to the underlying Socket on the TcpListener and call Shutdown on it:

_server.Stop();
_server.Server.Shutdown(SocketShutdown.Both);//now at your "read.ReadLine();" will throw SocketException

您在评论中表示:

实际上，我正在关闭侦听器在accept方法上返回的tcpclient.connClient.Close()

actually i'm closing the tcpclient returned by the listener on the accept method. connClient.Close()

如果要停止 tcpListerner " _server.Stop()"，然后关闭从 _server.AcceptTcpCleint()方法，然后在 reader.ReadLine()处将抛出 IOException:无法从传输连接中读取数据:阻塞操作被对WSACancelBlockingCall <的调用中断了/code>我自己进行了测试.

If are stopping the tcpListerner "_server.Stop()" and then close the clients getted from _server.AcceptTcpCleint() method, then at the at reader.ReadLine() will throw IOException: Unable to read data from the transport connection: A blocking operation was interrupted by a call to WSACancelBlockingCall I tested it myself.

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