ClientTest：

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



class TcpClientTest
{
    static void Main(string[] args)
    {
        try
        {
            // 创建一个TcpClient实例并连接到服务器  
            TcpClient client = new TcpClient("1vg5062570.51mypc.cn", 43319);
            //1vg5062570.51mypc.cn:43319
            // 获取一个NetworkStream对象以进行读写  
            NetworkStream stream = client.GetStream();

            // 将消息转换为字节数组  
            string message = "Hello from the client!";
            byte[] data = Encoding.ASCII.GetBytes(message);

            // 发送消息到服务器  
            stream.Write(data, 0, data.Length);

            // 读取服务器的响应  
            byte[] buffer = new byte[4096];
            int bytesRead = stream.Read(buffer, 0, buffer.Length);

            // 将接收到的字节转换为字符串  
            string responseData = Encoding.ASCII.GetString(buffer, 0, bytesRead);
            Console.WriteLine("Received from server: " + responseData);

            // 关闭连接  
            client.Close();
        }
        catch (Exception e)
        {
            Console.WriteLine("Error: " + e.Message);
        }

        // 等待用户按键，以便在控制台中查看结果  
        Console.WriteLine("Press Enter to continue...");
        Console.ReadLine();
    }
}

ClientTestV3：

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

public class IPport
{
    public string IP { get; set; }
    public int Port { get; set; }
}

namespace ClientTestV3
{
    internal class Program
    {
        static void Main(string[] args)
        {
            try
            {
                string jsonFilePath = "ipport.json"; // 替换为你的JSON文件路径  

                // 读取文件内容  
                string jsonContent = File.ReadAllText(jsonFilePath);

                // 反序列化JSON字符串到对象  
                IPport ipaddr = JsonConvert.DeserializeObject<IPport>(jsonContent);

                // 输出结果  
                Console.WriteLine($"{ipaddr.IP}:{ipaddr.Port}");

                // 创建一个TcpClient实例并连接到服务器  
                TcpClient client = new TcpClient($"{ipaddr.IP}", ipaddr.Port);

                // 获取一个NetworkStream对象以进行读写  
                NetworkStream stream = client.GetStream();


                // 将消息转换为字节数组  
                string message = "Hello from the client!";
                Random rand = new Random();
                message += rand.Next().ToString();
                byte[] data = Encoding.ASCII.GetBytes(message);

                // 发送消息到服务器  
                stream.Write(data, 0, data.Length);

                // 读取服务器的响应  
                byte[] buffer = new byte[4096];
                int bytesRead = stream.Read(buffer, 0, buffer.Length);

                // 将接收到的字节转换为字符串  
                string responseData = Encoding.ASCII.GetString(buffer, 0, bytesRead);
                Console.WriteLine("Received from server: " + responseData);
                Console.WriteLine("ReceivedBytes:{0}", bytesRead);
                // 关闭连接  
                client.Close();
            }
            catch (Exception e)
            {
                Console.WriteLine("Error: " + e.Message);
            }

            // 等待用户按键，以便在控制台中查看结果  
            Console.WriteLine("Press Enter to continue...");
            Console.ReadLine();
        }
    }
}