C#使用UdpClient发送和接收UDP数据示例

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

//本段代码中需要新增加的命名空间
using System.Net.Sockets;
using System.Net;
using System.Threading;

namespace WinForm1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
/// <summary>
/// 用于UDP发送的网络服务类
/// </summary>
private UdpClient udpcSend;
/// <summary>
/// 用于UDP接收的网络服务类
/// </summary>
private UdpClient udpcRecv;

/// <summary>
/// 按钮：发送数据
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnSend_Click(object sender, EventArgs e)
{
if (string.IsNullOrWhiteSpace(txtSendMssg.Text))
{
MessageBox.Show("请先输入待发送内容");
return;
}

// 匿名发送
//udpcSend = new UdpClient(0);             // 自动分配本地IPv4地址
// 实名发送
IPEndPoint localIpep = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 12345); // 本机IP，指定的端口号
udpcSend = new UdpClient(localIpep);
Thread thrSend = new Thread(SendMessage);
thrSend.Start(txtSendMssg.Text);
}

/// <summary>
/// 发送信息
/// </summary>
/// <param name="obj"></param>
private void SendMessage(object obj)
{
string message = (string)obj;
byte[] sendbytes = Encoding.Unicode.GetBytes(message);
IPEndPoint remoteIpep = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 8848); // 发送到的IP地址和端口号
udpcSend.Send(sendbytes, sendbytes.Length, remoteIpep);
udpcSend.Close();
ResetTextBox(txtSendMssg);
}

/// <summary>
/// 开关：在监听UDP报文阶段为true，否则为false
/// </summary>
bool IsUdpcRecvStart = false;
/// <summary>
/// 线程：不断监听UDP报文
/// </summary>
Thread thrRecv;

/// <summary>
/// 按钮：接收数据开关
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnRecv_Click(object sender, EventArgs e)
{
if (!IsUdpcRecvStart) // 未监听的情况，开始监听
{
IPEndPoint localIpep = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 8848); // 本机IP和监听端口号
udpcRecv = new UdpClient(localIpep);
thrRecv = new Thread(ReceiveMessage);
thrRecv.Start();
IsUdpcRecvStart = true;
ShowMessage(txtRecvMssg, "UDP监听器已成功启动");
}
else // 正在监听的情况，终止监听
{
thrRecv.Abort(); // 必须先关闭这个线程，否则会异常
udpcRecv.Close();
IsUdpcRecvStart = false;
ShowMessage(txtRecvMssg, "UDP监听器已成功关闭");
}
}

/// <summary>
/// 接收数据
/// </summary>
/// <param name="obj"></param>
private void ReceiveMessage(object obj)
{
IPEndPoint remoteIpep = new IPEndPoint(IPAddress.Any, 0);
while (true)
{
try
{
byte[] bytRecv = udpcRecv.Receive(ref remoteIpep);
string message = Encoding.Unicode.GetString(bytRecv, 0, bytRecv.Length);
ShowMessage(txtRecvMssg,string.Format("{0}[{1}]", remoteIpep, message));
}
catch (Exception ex)
{
ShowMessage(txtRecvMssg, ex.Message);
break;
}
}
}

// 向RichTextBox中添加文本
delegate void ShowMessageDelegate(RichTextBox txtbox, string message);
private void ShowMessage(RichTextBox txtbox, string message)
{
if (txtbox.InvokeRequired)
{
ShowMessageDelegate showMessageDelegate = ShowMessage;
txtbox.Invoke(showMessageDelegate, new object[] { txtbox, message });
}
else
{
txtbox.Text += message + "\r\n";
}
}

// 清空指定RichTextBox中的文本
delegate void ResetTextBoxDelegate(RichTextBox txtbox);
private void ResetTextBox(RichTextBox txtbox)
{
if (txtbox.InvokeRequired)
{
ResetTextBoxDelegate resetTextBoxDelegate = ResetTextBox;
txtbox.Invoke(resetTextBoxDelegate, new object[] { txtbox });
}
else
{
txtbox.Text = "";
}
}

/// <summary>
/// 关闭程序，强制退出
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
Environment.Exit(0);
}
}
}