关于socket服务用异步方式的问题。
下面的代码是从网找到的，能正常运行没有问题，我有一些问题：
1、TcpListener server 这些变量都是局部的，为什么还能正常工作。
2、我如何停止监听服务。
private void AcceptCallback(IAsyncResult ar)
{
TcpListener server = (TcpListener)ar.AsyncState;
ClientState state = new ClientState();
// Once the accept operation completes, this callback will
// be called. In it, you can create a new TcpClient in much
// the same way you did it in the synchronous code you had:
state.client = server.EndAcceptTcpClient(ar);
// We're going to start reading from the client's stream, and
// we need a buffer for that:
state.buffer = new byte[4096];
// Note that the TcpClient and the byte[] are both put into
// this "ClientState" object. We're going to need an easy
// way to get at those values in the callback for the read
// operation.
// Next, start a new accept operation so that we can process
// another client connection:
server.BeginAcceptTcpClient(AcceptCallback, server);
// Finally, start a read operation on the client we just
// accepted. Note that you could do this before starting the
// accept operation; the order isn't really important.
state.client.GetStream().BeginRead(state.buffer, 0,state.buffer.Length, ReadCallback, state);
}
private void ReadCallback(IAsyncResult ar)
{
ClientState state = (ClientState)ar.AsyncState;
int cbRead = state.client.GetStream().EndRead(ar);
if (cbRead == 0)
{
// The client has closed the connection
return;
}
// Your data is in state.buffer, and there are cbRead
// bytes to process in the buffer. This number may be
// anywhere from 1 up to the length of the buffer.
// The i/o completes when there is _any_ data to be read,
// not necessarily when the buffer is full.
// So, for example: 下面的是我的实现。
SockMsgStruct message = new SockMsgStruct();
message = (SockMsgStruct)ZhiKe.Serialization.ByteToObj(state.buffer);
StreamWriter f = new StreamWriter("c:/aa.txt",true);
f.WriteLine(message.MsgUid);
f.WriteLine(message.sMsg);
f.WriteLine(message.iMsgType);
f.Flush();
f.Close();
//textBox1.Text = textBox1.Text + strData + "/n/r";
// For ASCII you won't have to worry about partial characters
// but for pretty much any other common encoding you'll have to
// deal with that possibility, as there's no guarantee that an
// entire character will be transmitted in one piece.
// Of course, even with ASCII, you need to watch your string
// terminations. You'll have to either check the read buffer
// directly for a null terminator, or have some other means
// of detecting the actual end of a string. By the time the
// string goes through the decoding process, you'll have lost
// that information.
// As with the accept operation, we need to start a new read
// operation on this client, so that we can process the next
// bit of data that's sent:
state.client.GetStream().BeginRead(state.buffer, 0,state.buffer.Length, ReadCallback, state);
}
private void button1_Click(object sender, EventArgs e)
{
Int32 port = int.Parse(txtPort.Text);
IPAddress localAddr = IPAddress.Parse(cmbAddress.Text);
TcpListener server = new TcpListener(localAddr, port);
server.Start();
// The above is pretty much what you had, cleaned up
// a bit. All you have to do at this point is start
// an accept operation:
server.BeginAcceptTcpClient(AcceptCallback, server);
}
class ClientState
{
public TcpClient client;
public byte[] buffer;
}
[解决办法]
button1_Click里面创建TcpListener server ，然后使用异步回调AcceptCallback，“server.BeginAcceptTcpClient(AcceptCallback, server);”它带一个 IAsyncResult 类型的参数，就是说server 对象已经含在这个参数里了。
然后看代码
AcceptCallback(IAsyncResult ar)
{
TcpListener server = (TcpListener)ar.AsyncState;
这里，又从参数里把server 对象取出来了。
至于关闭监听的问题，
private void button1_Click(object sender, EventArgs e)
{
Int32 port = int.Parse(txtPort.Text);
IPAddress localAddr = IPAddress.Parse(cmbAddress.Text);
TcpListener server = new TcpListener(localAddr, port);
你改成
TcpListener server =null;
private void button1_Click(object sender, EventArgs e)
{
Int32 port = int.Parse(txtPort.Text);
IPAddress localAddr = IPAddress.Parse(cmbAddress.Text);
server = new TcpListener(localAddr, port);
...
}
最后需要关闭的时候，使用server .close()就行了
[解决办法]
这个异常是在关闭TCPListener时一定会引发的，你必须捕获并处理它。
