tcpipSocket/EAP/Client/Client.cs

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

namespace Client;

internal class Client
{
	static void Main(string[] args)
	{
		Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
		IPEndPoint endPoint = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 20000);

		SocketAsyncEventArgs arg = new SocketAsyncEventArgs();
		arg.RemoteEndPoint = endPoint;
		arg.Completed += ConnectCompleted;
		bool pending = socket.ConnectAsync(arg);
		if (!pending)
			ConnectCompleted(socket, arg);

		while (true)
		{
			Thread.Sleep(1000);
		}
	}

	private static void ConnectCompleted(object? sender, SocketAsyncEventArgs e)
	{
		if (sender == null || e == null)
			return;

		Socket socket = (Socket)sender;
		e.Dispose();

		string str = Console.ReadLine() ?? string.Empty;
		byte[] buffer = Encoding.UTF8.GetBytes(str);

		SocketAsyncEventArgs arg = new SocketAsyncEventArgs();
		arg.SetBuffer(buffer, 0, buffer.Length);
		arg.Completed += SendCompleted;
		bool pending = socket.SendAsync(arg);
		if (!pending)
			SendCompleted(socket, arg);
	}

	private static void SendCompleted(object? sender, SocketAsyncEventArgs e)
	{
		if (sender == null || e == null)
			return;

		Socket socket = (Socket)sender;

		string str = Console.ReadLine() ?? string.Empty;
		byte[] buffer = Encoding.UTF8.GetBytes(str);

		e.SetBuffer(buffer, 0, buffer.Length);
		bool pending = socket.SendAsync(e);
		if (!pending)
			SendCompleted(socket, e);
	}
}