我需要为工作中的一个项目编写TCP服务器，我在谷歌上搜索了如何做到这一点。我找到了一个MSDN答案，并设法让它正常运行，但我不知道如何获取数据以便能够来回接收。套接字最多只会保持连接约30秒钟（因为我的老板不希望计算机上的套接字保持打开状态）。这个类的目标是为我在主程序中提供一种快速检索有关计算机及其用户的数据的方法。
目前，我正在尝试制作一个简单的版本，在连接时客户端会接收到来自服务器的数据包，上面写着类似于“来自网络的问候！”之类的内容。但是我一直在遇到一些奇怪的异常。以上代码基本上是从MSDN上“复制”下来的。我在编写时参考了MSDN的示例，但仍需要进行一些修改（例如去除阻塞性质）。目前，我只想知道如何将数据从主机发送给连接的客户端！:(
从命名空间的名称可以猜出它是为计算机实验室设计的。
namespace LabAssist.Server.Common.Objects {
using Atlantis.Net.Sockets;
using LabAssist.Server.Common.Data;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Windows.Forms;
public class TcpServer {
#region Constructor(s)
public TcpServer(IPEndPoint endPoint) {
RemoteEndPoint = endPoint;
Host = new Socket(RemoteEndPoint.Address.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
}
public TcpServer(String hostNameOrIpAddress, Int32 port) {
RemoteEndPoint = new IPEndPoint(Dns.GetHostEntry(hostNameOrIpAddress).AddressList[0], port);
Host = new Socket(RemoteEndPoint.Address.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
}
public TcpServer(Int32 port) {
RemoteEndPoint = new IPEndPoint(Dns.GetHostEntry(Dns.GetHostName()).AddressList[0], port);
Host = new Socket(RemoteEndPoint.Address.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
}
#endregion
#region Fields
private Boolean m_IsBound = false;
private List<Socket> m_Connections = new List<Socket>(50); // allow 50 sockets
private static System.Threading.ManualResetEvent AllDone = new System.Threading.ManualResetEvent(false);
#endregion
#region Properties
private Int32 m_Backlog = 32;
/// <summary>
/// Gets or sets the number of connections the host can accept at any given point
/// </summary>
public Int32 Backlog {
set {
m_Backlog = value;
}
get {
return m_Backlog;
}
}
private Socket m_Host = null;
/// <summary>
/// Gets or sets the host master socket
/// </summary>
public Socket Host {
private set {
m_Host = value;
}
get {
return m_Host;
}
}
private Int32 m_Port = 1337;
/// <summary>
/// Gets or sets the binding port for the server
/// </summary>
public Int32 Port {
set {
m_Port = value;
}
get {
return m_Port;
}
}
private IPEndPoint m_EndPoint = null;
/// <summary>
/// Gets or sets the binding address to be used when binding the socket
/// </summary>
public IPEndPoint RemoteEndPoint {
private set {
m_EndPoint = value;
}
get { // follows a singleton pattern with a private-setter.
if (m_EndPoint == null) {
RemoteEndPoint = new IPEndPoint(Dns.GetHostEntry(Dns.GetHostName()).AddressList[0], Port);
}
return m_EndPoint;
}
}
#endregion
#region Methods
private void AcceptCallback(IAsyncResult ar) {
Socket client = ((Socket)ar.AsyncState);
Socket handler = client.EndAccept(ar);
m_Connections.Add(handler);
AllDone.Set();
Console.WriteLine("Client accepted.\t Remote address and port : {0}", handler.RemoteEndPoint.ToString());
Byte[] buf = Encoding.ASCII.GetBytes("hello world. This is my first TCP Server >:)");
Int32 ret = 0;
Boolean ext = false;
//try-catch temporary until sending is figured out. ><
try {
ret = client.Send(buf, buf.Length, SocketFlags.None);
} catch (Exception ex) {
ext = true;
ConsoleColor c = Console.ForegroundColor;
Console.ForegroundColor = ConsoleColor.Yellow;
Console.WriteLine(ex.ToString());
Console.ForegroundColor = c;
}
// error check for debugging
if (ret > 0) {
Console.WriteLine("Sent -> {0}", Encoding.ASCII.GetString(buf, 0, buf.Length));
} else {
if (ext) {
ConsoleColor c = Console.ForegroundColor;
Console.ForegroundColor = ConsoleColor.Red;
Console.WriteLine("Caught an exception");
Console.ForegroundColor = c;
}
Console.WriteLine("Failed to send welcome packet to client.");
}
State state = new State();
state.WorkSocket = handler;
handler.BeginReceive(state.Buffer, 0, State.BufferSize, 0, new AsyncCallback(ReceiveDataCallback), state);
}
/// <summary>
/// Intialises the socket to listen and begins to accept connections
/// </summary>
/// <returns></returns>
public void Initialise() {
Host.Bind(RemoteEndPoint);
Console.WriteLine("Local address and port : {0}", RemoteEndPoint.ToString());
m_IsBound = true;
Host.Listen(Backlog);
try {
while (true) {
AllDone.Reset();
Console.WriteLine("Awaiting{0} client connection...", (m_Connections.Count > 0 ? " another" : ""));
Host.BeginAccept(new AsyncCallback(AcceptCallback), Host);
AllDone.WaitOne();
Application.DoEvents();
}
} catch (Exception e) {
Log.HandledException(e);
}
}
private void ReceiveDataCallback(IAsyncResult ar) {
State state = ((State)ar.AsyncState);
Socket handler = state.WorkSocket;
if (!handler.IsConnected()) {
return;
}
Int32 read = handler.EndReceive(ar);
if (read > 0) {
state.DataReceived.Append(Encoding.ASCII.GetString(state.Buffer, 0, read));
handler.BeginReceive(state.Buffer, 0, State.BufferSize, SocketFlags.None, new AsyncCallback(ReceiveDataCallback), state);
} else {
if (state.DataReceived.Length > 1) {
String content = state.DataReceived.ToString();
Console.WriteLine("Read {0} bytes from socket.\n Data: {1}", content.Length, content);
}
handler.Close();
}
}
#endregion
}
}
目前，我正在尝试制作一个简单的版本，在连接时客户端会接收到来自服务器的数据包，上面写着类似于“来自网络的问候！”之类的内容。但是我一直在遇到一些奇怪的异常。以上代码基本上是从MSDN上“复制”下来的。我在编写时参考了MSDN的示例，但仍需要进行一些修改（例如去除阻塞性质）。目前，我只想知道如何将数据从主机发送给连接的客户端！:(
System.Net.Sockets.SocketException: A request to send or receive data was disall owed because the socket is not connected and (when sending on a datagram socket using a sendto call) no address was supplied
at System.Net.Sockets.Socket.Send(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags)
at System.Net.Sockets.Socket.Send(Byte[] buffer, Int32 size, SocketFlags socketFlags)
at LabAssist.Server.Common.Objects.TcpServer.AcceptCallback(IAsyncResult ar) in F:\Source\ACCL\Lab Suite\Code\LabAssist.Server\Common\Objects\TcpServer.cs:li
ne 119