1、文件结构

2、UdpReceiver.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading.Tasks;

namespace UDPTest.Udp
{
    public class UdpStateEventArgs : EventArgs
    {
        public IPEndPoint remoteEndPoint;
        public byte[] buffer = null;
    }
    public delegate void UdpReceivedEventHandler(UdpStateEventArgs args);
    public class UdpReceiver
    {
        private UdpClient udpClient;
        public event UdpReceivedEventHandler UdpReceived;
        public UdpReceiver(string localIp,int localPort, string remoteIp, int remotePort)
        {
            IPEndPoint localPoint = new IPEndPoint(IPAddress.Parse(localIp), localPort);
            udpClient = new UdpClient(localPoint);
            Task.Run(() =>
            {
                while (true)
                {
                    UdpStateEventArgs args = new UdpStateEventArgs();
                    if (udpClient != null)
                    {
                        IPEndPoint remotePoint = new IPEndPoint(IPAddress.Parse(remoteIp), remotePort);
                        var received = udpClient.Receive(ref remotePoint);
                        args.remoteEndPoint = remotePoint;
                        args.buffer = received;
                        UdpReceived?.Invoke(args);
                    }
                    else
                    {
                        break;
                    }
                }
            });
        }
    }
}

3、ControlCross.cs

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

namespace UDPTest.Utils
{
    internal class ControlCross
    {
        public static void LableSetText(Label label, string text)
        {
            if (label.InvokeRequired)
            {
                MethodInvoker mi = delegate ()
                {
                    label.Text = text;
                };
                label.Invoke(mi);
            }
            else
            {
                label.Text = text;
            }
        }
    }
}

4、MainForm窗口

5、MainForm.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using UDPTest.Udp;
using UDPTest.Utils;

namespace UDPTest
{
    public partial class MainForm : Form
    {
        public MainForm()
        {
            InitializeComponent();
        }

        string localIp="127.0.0.1";
        int localPort = 7777;
        string remoteIp = "127.0.0.1";
        int remotePort = 8081;
        string remotePointInfo = "";
        string receiveBuffer = "";
        

        private void btStartTest_Click(object sender, EventArgs e)
        {
            UdpReceiver udpReceiver=new UdpReceiver(localIp, localPort, remoteIp, remotePort);
            udpReceiver.UdpReceived += UdpReceiverProcess;
        }

        private void UdpReceiverProcess(UdpStateEventArgs args)
        {
            var remotePoint = args.remoteEndPoint;
            remotePointInfo = $"{remotePoint.Address}:{remotePoint.Port}";
            receiveBuffer = Encoding.UTF8.GetString(args.buffer);
            ControlCross.LableSetText(lbTest1, remotePointInfo);
            ControlCross.LableSetText(lbTest2, receiveBuffer);
        }

        private UdpClient udpClient = null;
        private void btSendSet_Click(object sender, EventArgs e)
        {
            IPEndPoint localPoint = new IPEndPoint(IPAddress.Parse(localIp), localPort);
            udpClient = new UdpClient(localPoint);
        }

        private void btSendTest_Click(object sender, EventArgs e)
        {
            string str=this.tbSendData.Text;
            byte[] buffer=Encoding.UTF8.GetBytes(str);
            if(udpClient != null)
            {
                IPEndPoint remotePoint = new IPEndPoint(IPAddress.Parse(remoteIp), remotePort);
                udpClient.Send(buffer,buffer.Length,remotePoint);
            }
        }
    }
}

6、运行代码