C# 通过广播实现局域网自动连接

两台局域网电脑A B 分别设置isSender 为true和false，就可以实现自动寻找与连接。

using System.Net;
using System.Net.Sockets;
using System.Text;

Console.WriteLine("Hello, World!");

var port = 8056;

var sock = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
//255.255.255.255 
EndPoint sendEndPoint = new IPEndPoint(IPAddress.Broadcast, port);
EndPoint receiveEndPoint = new IPEndPoint(IPAddress.Any, port);

sock.Bind(receiveEndPoint);
var isSender = false;
var sendStr = "Hello World!";
if (isSender)
{
    sock.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.Broadcast, 1);
    var data = Encoding.UTF8.GetBytes(sendStr);

    new Thread(OnReceive).Start();

    while (true)
    {
        sock.SendTo(data, sendEndPoint);
        Thread.Sleep(1000);
    }
}
else
{
    var data = new byte[1024];
    var response = Encoding.UTF8.GetBytes("VR");
    while (true)
    {
        var length = sock.ReceiveFrom(data, ref receiveEndPoint);
        var ipEndPoint = receiveEndPoint as IPEndPoint;
        if (ipEndPoint is not null)
        {
            var str = Encoding.UTF8.GetString(data, 0, length);
            Console.WriteLine($"{ipEndPoint.Address}:{ipEndPoint.Port}> {str}");
            sock.SendTo(response, receiveEndPoint);
        }
    }
}

void OnReceive()
{
    var data = new byte[1024];
    while (true)
    {
        var length = sock.ReceiveFrom(data, ref receiveEndPoint);
        var ipEndPoint = receiveEndPoint as IPEndPoint;
        if (ipEndPoint is not null)
        {
            var str = Encoding.UTF8.GetString(data, 0, length);
            if (str == sendStr)
            {
                continue;
            }
            Console.WriteLine($"{ipEndPoint.Address}:{ipEndPoint.Port}> {str}");
        }
    }
}