了解c＃tcp异步客户端程序时遇到大问题！我已经编写了下一个代码（主要来自微软开发人员网络，我只将console.writeline更改为我的WPF应用程序的lambda表达式），这里的问题是我收到错误＆＃34;发送或接收数据的请求被禁止，因为socket没有连接（当使用send to call在数据报套接字上发送时）没有提供地址＆＃34;！
如果应用程序在我第一次连接到服务器时显示该消息，我不介意，但是当我第二次连接时会出现此错误。 它说我没有提供地址，但为什么它第一次工作但不是第二次，当我用相同的地址连接时？
PS：我认为问题出在服务器应用中，因为我检查了所有内容（与MSDN网站相同）！
CODE：
// State object for receiving data from remote device.
public class StateObject {
// Client socket.
public Socket workSocket = null;
// Size of receive buffer.
public const int BufferSize = 256;
// Receive buffer.
public byte[] buffer = new byte[BufferSize];
// Received data string.
public StringBuilder sb = new StringBuilder();
}
public class AsynchronousClient
{
// The port number for the remote device.
private static int port;
private static IPAddress ipAd;
public static TextBlock statusPanel;
// ManualResetEvent instances signal completion.
private static ManualResetEvent connectDone =
new ManualResetEvent(false);
private static ManualResetEvent sendDone =
new ManualResetEvent(false);
private static ManualResetEvent receiveDone =
new ManualResetEvent(false);
// The response from the remote device.
private static String response = String.Empty;
public static void setPort(int portt)
{
port = portt;
}
public static void setIpAddress(string ip)
{
ipAd = IPAddress.Parse(ip);
}
public static void setStatusPanel(TextBlock status)
{
statusPanel = status;
}
public static void StartClient(string message)
{
// Connect to a remote device.
try
{
// Establish the remote endpoint for the socket.
IPAddress ipAddress = ipAd;
IPEndPoint remoteEP = new IPEndPoint(ipAddress, port);
// Create a TCP/IP socket.
Socket client = new Socket(AddressFamily.InterNetwork,
SocketType.Stream, ProtocolType.Tcp);
// Connect to the remote endpoint. IMPORTANT: AsyncCallback will be called on seperate thread
client.BeginConnect(remoteEP,
new AsyncCallback(ConnectCallback), client);
connectDone.WaitOne();
// Send test data to the remote device.
string sendingMessage = message + "<EOF>";
Send(client, sendingMessage);
sendDone.WaitOne();
// Receive the response from the remote device.
Receive(client);
receiveDone.WaitOne();
// Write the response to the console.
//statusPanel.Text += "Response received: " + response + "\n\n";
// Release the socket.
client.Shutdown(SocketShutdown.Both);
client.Close();
}
catch (Exception e)
{
statusPanel.Dispatcher.BeginInvoke(new Action(() =>
statusPanel.Text += e.ToString() + "\n"
));
}
}
public static void ConnectCallback(IAsyncResult ar)
{
try
{
// Retrieve the socket from the state object.
Socket client = (Socket)ar.AsyncState;
// Complete the connection.
client.EndConnect(ar);
//string remote = client.RemoteEndPoint.ToString();
// statusPanel.Dispatcher.BeginInvoke(new Action(() =>
// statusPanel.Text = "Message send to: " + remote + "\n"
// ));
// Signal that the connection has been made.
connectDone.Set();
}
catch (Exception e)
{
statusPanel.Dispatcher.BeginInvoke(new Action(() =>
statusPanel.Text += e.ToString() + "\n"
));
}
}
private static void Receive(Socket client)
{
try
{
// Create the state object.
StateObject state = new StateObject();
state.workSocket = client;
// FOLLOWING LINE IS WHERE THE PROGRAM CHRASHES
client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(ReceiveCallback), state);
}
catch (Exception e)
{
statusPanel.Dispatcher.BeginInvoke(new Action(() =>
statusPanel.Text += e.ToString() + "\n"
));
}
}
private static void ReceiveCallback(IAsyncResult ar)
{
try
{
// Retrieve the state object and the client socket
// from the asynchronous state object.
StateObject state = (StateObject)ar.AsyncState;
Socket client = state.workSocket;
// Read data from the remote device.
int bytesRead = client.EndReceive(ar);
if (bytesRead > 0)
{
// There might be more data, so store the data received so far.
state.sb.Append(Encoding.ASCII.GetString(state.buffer, 0, bytesRead));
// Get the rest of the data.
client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(ReceiveCallback), state);
}
else
{
// All the data has arrived; put it in response.
if (state.sb.Length > 1)
{
response = state.sb.ToString();
}
// Signal that all bytes have been received.
receiveDone.Set();
}
}
catch (Exception e)
{
statusPanel.Dispatcher.BeginInvoke(new Action(() =>
statusPanel.Text += e.ToString() + "\n"
));
}
}
private static void Send(Socket client, String data)
{
// Convert the string data to byte data using ASCII encoding.
byte[] byteData = Encoding.ASCII.GetBytes(data);
// Begin sending the data to the remote device.
client.BeginSend(byteData, 0, byteData.Length, 0,
new AsyncCallback(SendCallback), client);
}
private static void SendCallback(IAsyncResult ar)
{
try
{
// Retrieve the socket from the state object.
Socket client = (Socket)ar.AsyncState;
// Signal that all bytes have been sent.
sendDone.Set();
}
catch (Exception e)
{
statusPanel.Dispatcher.BeginInvoke(new Action(() =>
statusPanel.Text += e.ToString() + "\n"
));
}
}
}
答案 0 :(得分：0)
由于连接事件在第一次连接后处于设置状态，因此第二次尝试在实际连接完成之前发送。 connectDone，sendDone＆amp; receiveDone是ManualResetEvent，你需要在开始第二次连接之前重置，发送＆amp;接收。