【发布时间】：2015-01-08 22:17:16
【问题描述】：
我继承了一些用于 TCP 客户端的代码。它发送一条消息，然后在完成时等待确认消息。目前它发送消息，但是当它等待回复消息时，它永远不会收到它。 SendMessage() 方法是外部调用的。
我设置了断点，可以看到它命中了Receive() 方法，但从来没有命中ReceiveCallback()
感谢您向正确方向提供任何帮助或推动。
public class SocketService
{
private ManualResetEvent connectDone = new ManualResetEvent(false);
private ManualResetEvent sendDone = new ManualResetEvent(false);
private ManualResetEvent receiveDone = new ManualResetEvent(false);
string ipAddress;
private int portNum;
string returnMessage;
// private string hostName = Dns.GetHostName ();
public SocketService(string ipAddress, int portNum)
{
this.ipAddress = ipAddress;
this.portNum = portNum;
}
public event Logging OnLogging;
private void WriteLogMessage(string message)
{
if (this.OnLogging != null)
this.OnLogging(message);
}
//char endOfLineSeparator = (char) 0x1C;
//char cr = (char) 0x0D;
//char vt = (char) 0x0B;
public string SendMessage(string message)
{
IPAddress ip = IPAddress.Parse(this.ipAddress);
IPEndPoint remoteEP = new IPEndPoint(ip, portNum);
connectDone.Reset();
Socket client = new Socket(AddressFamily.InterNetwork,
SocketType.Stream,
ProtocolType.Tcp);
client.BeginConnect(remoteEP,
new AsyncCallback(ConnectCallback),
client);
connectDone.WaitOne();
//sendDone.Reset();
WriteLogMessage("send message");
Send(client, message);
sendDone.WaitOne();
//receiveDone.Reset();
WriteLogMessage("receive message");
Receive(client);
receiveDone.WaitOne();
client.Shutdown(SocketShutdown.Both);
client.Close();
return this.returnMessage;
}
private void Send(Socket client, String data)
{
byte[] byteData = Encoding.ASCII.GetBytes(data);
client.BeginSend(byteData,
0,
byteData.Length,
0,
new AsyncCallback(SendCallback),
client);
}
private void SendCallback(IAsyncResult ar)
{
Socket client = (Socket)ar.AsyncState;
int bytesSent = client.EndSend(ar);
sendDone.Set();
}
private void ConnectCallback(IAsyncResult ar)
{
Socket client = (Socket)ar.AsyncState;
client.EndConnect(ar);
connectDone.Set();
}
private void Receive(Socket client)
{
StateObject state = new StateObject(client);
client.BeginReceive(state.Buffer,
0,
StateObject.BufferSize,
0,
new AsyncCallback(ReceiveCallback),
state);
}
private void ReceiveCallback(IAsyncResult ar)
{
StateObject state = (StateObject)ar.AsyncState;
Socket client = state.WorkSocket;
int bytesRead = client.EndReceive(ar);
if (bytesRead > 0)
{
state.StoredContent.Append(Encoding.ASCII.GetString(state.Buffer, 0, bytesRead));
client.BeginReceive(state.Buffer,
0,
StateObject.BufferSize,
0,
new AsyncCallback(ReceiveCallback),
state);
WriteLogMessage(state.StoredContent.ToString());
}
else
{
this.returnMessage = state.StoredContent.ToString();
receiveDone.Set();
}
}
}
【问题讨论】：
-
评论你所有的
ManualResetEvents 然后再试一次，你得到ReceiveCallback调用了吗？ -
根据您在 TCP 上实现的协议，“消息”的定义是什么？对方如何知道它已收到完整的消息，以便知道要响应？
-
顺便说一句：同步回调不是一件容易的事，我建议使用 awaitable async 方法，如
SendTaskAsync，ReceiveTaskAsync等.