我看到很多关于处理套接字时出现对象已释放异常的问题,因此我决定尝试一下,看看是否可以解决。以下是我的发现。
问题?
你有一段代码,使用了来自System.Net.Sockets的Socket作为服务器套接字。问题是你想关闭套接字,但每次尝试时都会出现ObjectDisposedException异常。
你的代码可能类似于这样:
private static ManualResetEvent allDone = new ManualResetEvent(false);
private Socket ear;
public void Start()
{
new Thread(() => StartListening()).Start();
}
private void StartListening()
{
IP = Dns.GetHostAddresses(Dns.GetHostName()).Where(address => address.AddressFamily == AddressFamily.InterNetwork).First();
port = 11221;
IPEndPoint localEndPoint = new IPEndPoint(IP, Port);
ear = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
ear.Bind(localEndPoint);
ear.Listen(100);
try
{
while (true)
{
allDone.Reset();
ear.BeginAccept(new AsyncCallback(AcceptCallback), ear);
allDone.WaitOne();
}
}
catch (ObjectDisposedException e)
{
Console.WriteLine("Socket Closed");
}
}
private void AcceptCallback(IAsyncResult ar)
{
allDone.Set();
Socket listener = (Socket)ar.AsyncState;
Socket handler = listener.EndAccept(ar);
StateObject state = new StateObject();
state.workSocket = handler;
handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0, new AsyncCallback(ReadCallback), state);
}
public static void ReadCallback(IAsyncResult ar)
{
String content = String.Empty;
StateObject state = (StateObject) ar.AsyncState;
Socket handler = state.workSocket;
int bytesRead = handler.EndReceive(ar);
if (bytesRead > 0) {
state.sb.Append(Encoding.ASCII.GetString(state.buffer,0,bytesRead));
content = state.sb.ToString();
if (content.IndexOf("<EOF>") > -1) {
Console.WriteLine("Read {0} bytes from socket. \n Data : {1}", content.Length, content );
}
else
{
handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(ReadCallback), state);
}
}
}
public void Stop()
{
ear.Close();
}
运行类似上述代码将导致在尝试结束接收时出现AcceptCallback错误。即使您捕获了该错误,仍会在StartListening()方法中出现错误。