求助：通常每个套接字地址通常每个套接字地址(协议/网络地址/端口)只允许使用一次
“UDP_Server = new UdpClient(localPort); //创建一个新的端口号” 这一句这里，总是报错：通常每个套接字地址通常每个套接字地址(协议/网络地址/端口)只允许使用一次
这是一个即时通讯的程序。
using System;using System.ComponentModel;using System.Collections.Generic;using System.Diagnostics;using System.Linq;using System.Text;using System.Net.Sockets;using System.Net;using System.Windows.Forms;using System.Threading;namespace QQClass{ public partial class UDPSocket : Component { private IPEndPoint ServerEndPoint = null; //定义网络端点 private UdpClient UDP_Server = new UdpClient(); //创建网络服务,也就是UDP的Sockets private System.Threading.Thread thdUdp; //创建一个线程 public delegate void DataArrivalEventHandler(byte[] Data, IPAddress Ip, int Port); //定义了一个托管方法 public event DataArrivalEventHandler DataArrival; //通过托管在控件中定义一个事件 private string localHost = "127.0.0.1"; [Browsable(true), Category("Local"), Description("本地IP地址")] //在“属性”窗口中显示localHost属性 public string LocalHost { get { return localHost; } set { localHost = value; } } private int localPort = 11000; [Browsable(true), Category("Local"), Description("本地端口号")] //在“属性”窗口中显示localPort属性 public int LocalPort { get { return localPort; } set { localPort = value; } } private bool active = false; [Browsable(true), Category("Local"), Description("激活监听")] //在“属性”窗口中显示active属性 public bool Active { get { return active; } set //该属性读取值 { active = value; if (active) //当值为True时 { OpenSocket(); //打开监听 } else { CloseSocket(); //关闭监听 } } } public UDPSocket() { InitializeComponent(); } public UDPSocket(IContainer container) { container.Add(this); InitializeComponent(); } protected void Listener() //监听 { ServerEndPoint = new IPEndPoint(IPAddress.Any,localPort); //将IP地址和端口号以网络端点存储 if (UDP_Server != null) UDP_Server.Close(); [color=#FF0000]UDP_Server = new UdpClient(localPort); //创建一个新的端口号[/color] UDP_Server.Client.ReceiveBufferSize = 1000000000; //接收缓冲区大小 UDP_Server.Client.SendBufferSize = 1000000000; //发送缓冲区大小 try { thdUdp = new Thread(new ThreadStart(GetUDPData)); //创建一个线程 thdUdp.Start(); //执行当前线程 } catch (Exception e) { MessageBox.Show(e.ToString()); //显示线程的错误信息 } } private void GetUDPData() //获取当前接收的消息 { while (active) { try { byte[] Data = UDP_Server.Receive(ref ServerEndPoint); //将获取的远程消息转换成二进制流 if (DataArrival != null) { DataArrival(Data, ServerEndPoint.Address, ServerEndPoint.Port); } Thread.Sleep(0); } catch { } } } private void CallBackMethod(IAsyncResult ar) { //从异步状态ar.AsyncState中，获取委托对象 DataArrivalEventHandler dn = (DataArrivalEventHandler)ar.AsyncState; //一定要EndInvoke，否则你的下场很惨 dn.EndInvoke(ar); } public void Send(System.Net.IPAddress Host, int Port, byte[] Data) { try { IPEndPoint server = new IPEndPoint(Host, Port); UDP_Server.Send(Data, Data.Length, server); } catch (Exception e) { MessageBox.Show(e.ToString()); } } private void OpenSocket() { Listener(); } private void CloseSocket() { if (UDP_Server != null) UDP_Server.Close(); if (thdUdp != null) { Thread.Sleep(30); thdUdp.Abort(); } } }}