tcpipSocket/APM/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);

		socket.BeginConnect(endPoint, ConnectCompleted, socket);

		while (true)
		{
			string str = Console.ReadLine() ??	string.Empty;
			socket.Send(Encoding.UTF8.GetBytes(str));
		}
	}

	private static void ConnectCompleted(IAsyncResult ar)
	{
		if (ar.AsyncState == null)
			return;

		Socket socket = (Socket)ar.AsyncState;
		socket.EndConnect(ar);

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

		socket.BeginSend(buffer, 0, buffer.Length, SocketFlags.None, SendCompleted, socket);
	}

	private static void SendCompleted(IAsyncResult ar)
	{
		if (ar.AsyncState == null)
			return;

		Socket socket = (Socket)ar.AsyncState;
		socket.EndSend(ar);

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

		socket.BeginSend(buffer, 0, buffer.Length, SocketFlags.None, SendCompleted, socket);
	}
}