UdpClient 类在同步阻塞模式中为发送和接收无连接的 UDP 数据包而提供了简单的方法。因为 UDP 是一种无连接的传输协议,所以你不需要在发送和接收数据之前建立任何远程主机连接。你只需要按照下列方式来建立默认的远程主机选项:
使用远程主机名称和端口号作为参数来创建 UdpClient 类的实例。
创建 UdpClient 类的实例然后调用 Connect 方法。
你可以使用任何由 UdpClient 所提供的发送方法把数据发送给远程设备。然后使用 Receive 方法来接收来自于远程主机的数据。
提示:如果你已经指定了一个默认的远程主机,就不要使用主机名称或者 IPEndPoint 来调用 Send 方法。如果你这样做,那么 UdpClient 将会抛出一个异常。
UdpClient 方法同样允许你发送和接收多点传送的数据包。而使用 JoinMulticastGroup 方法可以把 UdpClient 订阅到多点传送分组。也可以使用 DropMulticastGroup 方法把 UdpClient 从多点传送分组的订阅中取消。
本节介绍使用UdpClient实现一个同步的UDP服务器
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Net.Sockets; using System.Net; using System.Threading; namespace NetFrame.Net.UDP.Listener.Synchronous { /// <summary> /// UdpClient 实现同步UDP服务器 /// </summary> public class UDPServer { #region Fields /// <summary> /// 服务器程序允许的最大客户端连接数 /// </summary> private int _maxClient; /// <summary> /// 当前的连接的客户端数 /// </summary> //private int _clientCount; /// <summary> /// 服务器使用的异步UdpClient /// </summary> private UdpClient _server; /// <summary> /// 客户端会话列表 /// </summary> //private List<UDPState> _clients; private bool disposed = false; /// <summary> /// 数据接受缓冲区 /// </summary> private byte[] _recvBuffer; #endregion #region Properties /// <summary> /// 服务器是否正在运行 /// </summary> public bool IsRunning { get; private set; } /// <summary> /// 监听的IP地址 /// </summary> public IPAddress Address { get; private set; } /// <summary> /// 监听的端口 /// </summary> public int Port { get; private set; } /// <summary> /// 通信使用的编码 /// </summary> public Encoding Encoding { get; set; } #endregion #region 构造函数 /// <summary> /// 同步UdpClient UDP服务器 /// </summary> /// <param name="listenPort">监听的端口</param> public UDPServer(int listenPort) : this(IPAddress.Any, listenPort,1024) { } /// <summary> /// 同步UdpClient UDP服务器 /// </summary> /// <param name="localEP">监听的终结点</param> public UDPServer(IPEndPoint localEP) : this(localEP.Address, localEP.Port,1024) { } /// <summary> /// 同步UdpClient UDP服务器 /// </summary> /// <param name="localIPAddress">监听的IP地址</param> /// <param name="listenPort">监听的端口</param> /// <param name="maxClient">最大客户端数量</param> public UDPServer(IPAddress localIPAddress, int listenPort, int maxClient) { this.Address = localIPAddress; this.Port = listenPort; this.Encoding = Encoding.Default; _maxClient = maxClient; //_clients = new List<AsyncUDPSocketState>(); _server = new UdpClient(new IPEndPoint(this.Address, this.Port)); _recvBuffer=new byte[_server.Client.ReceiveBufferSize]; } #endregion #region Method /// <summary> /// 启动服务器 /// </summary> /// <returns>异步TCP服务器</returns> public void Start() { if (!IsRunning) { IsRunning = true; _server.EnableBroadcast = true; new Thread(ReceiveData).Start(); } } /// <summary> /// 停止服务器 /// </summary> public void Stop() { if (IsRunning) { IsRunning = false; _server.Close(); //TODO 关闭对所有客户端的连接 } } /// <summary> /// 同步接收数据的方法 /// </summary> /// <param name="ar"></param> private void ReceiveData() { IPEndPoint remote = null; while (true) { byte[] buffer = null; try { buffer = _server.Receive(ref remote); } catch (Exception) { //异常处理操作 return; } if (buffer == null || buffer.Length == 0) return; //TODO 数据包收到触发事件 RaiseDataReceived(null); } } /// <summary> /// 同步发送数据 /// </summary> /// <param name="msg"></param> /// <param name="remote"></param> public void Send(string msg, IPEndPoint remote) { byte[] data = Encoding.Default.GetBytes(msg); try { _server.Send(data, data.Length, remote); } catch (Exception) { //TODO 异常处理 RaiseOtherException(null); } } #endregion #region 事件 /// <summary> /// 接收到数据事件 /// </summary> public event EventHandler<UDPEventArgs> DataReceived; private void RaiseDataReceived(UDPState state) { if (DataReceived != null) { DataReceived(this, new UDPEventArgs(state)); } } /// <summary> /// 数据发送完毕事件 /// </summary> public event EventHandler<UDPEventArgs> CompletedSend; /// <summary> /// 触发数据发送完毕的事件 /// </summary> /// <param name="state"></param> private void RaiseCompletedSend(UDPState state) { if (CompletedSend != null) { CompletedSend(this, new UDPEventArgs(state)); } } /// <summary> /// 网络错误事件 /// </summary> public event EventHandler<UDPEventArgs> NetError; /// <summary> /// 触发网络错误事件 /// </summary> /// <param name="state"></param> private void RaiseNetError(UDPState state) { if (NetError != null) { NetError(this, new UDPEventArgs(state)); } } /// <summary> /// 异常事件 /// </summary> public event EventHandler<UDPEventArgs> OtherException; /// <summary> /// 触发异常事件 /// </summary> /// <param name="state"></param> private void RaiseOtherException(UDPState state, string descrip) { if (OtherException != null) { OtherException(this, new UDPEventArgs(descrip, state)); } } private void RaiseOtherException(UDPState state) { RaiseOtherException(state, ""); } #endregion #region Close /// <summary> /// 关闭一个与客户端之间的会话 /// </summary> /// <param name="state">需要关闭的客户端会话对象</param> public void Close(UDPState state) { if (state != null) { //_clients.Remove(state); //_clientCount--; //TODO 触发关闭事件 } } /// <summary> /// 关闭所有的客户端会话,与所有的客户端连接会断开 /// </summary> public void CloseAllClient() { //foreach (AsyncUDPSocketState client in _clients) //{ // Close(client); //} //_clientCount = 0; //_clients.Clear(); } #endregion #region 释放 /// <summary> /// Performs application-defined tasks associated with freeing, /// releasing, or resetting unmanaged resources. /// </summary> public void Dispose() { Dispose(true); GC.SuppressFinalize(this); } /// <summary> /// Releases unmanaged and - optionally - managed resources /// </summary> /// <param name="disposing"><c>true</c> to release /// both managed and unmanaged resources; <c>false</c> /// to release only unmanaged resources.</param> protected virtual void Dispose(bool disposing) { if (!this.disposed) { if (disposing) { try { Stop(); if (_server != null) { _server = null; } } catch (SocketException) { //TODO RaiseOtherException(null); } } disposed = true; } } #endregion } }
用户状态封装类
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Net.Sockets; using System.Net; namespace NetFrame.Net.UDP.Listener.Synchronous { public class UDPState { // Client socket. public UdpClient udpClient = null; // Size of receive buffer. public const int BufferSize = 1024; // Receive buffer. public byte[] buffer = new byte[BufferSize]; // Received data string. public StringBuilder sb = new StringBuilder(); public IPEndPoint remote = new IPEndPoint(IPAddress.Any, 0); } }
服务器事件参数类
using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace NetFrame.Net.UDP.Listener.Synchronous { /// <summary> /// UdpClient 同步UDP服务器事件类 /// </summary> public class UDPEventArgs : EventArgs { /// <summary> /// 提示信息 /// </summary> public string _msg; /// <summary> /// 客户端状态封装类 /// </summary> public UDPState _state; /// <summary> /// 是否已经处理过了 /// </summary> public bool IsHandled { get; set; } public UDPEventArgs(string msg) { this._msg = msg; IsHandled = false; } public UDPEventArgs(UDPState state) { this._state = state; IsHandled = false; } public UDPEventArgs(string msg, UDPState state) { this._msg = msg; this._state = state; IsHandled = false; } } }
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