在C#中，使用TcpClient進行SSL/TLS加密通信需要使用SslStream類

using System;
using System.IO;
using System.Net.Security;
using System.Net.Sockets;
using System.Security.Authentication;
using System.Text;

namespace TcpClientSslDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            // 服務器地址和端口
            string serverAddress = "example.com";
            int serverPort = 443;

            // 創建TcpClient實例
            using (TcpClient client = new TcpClient(serverAddress, serverPort))
            {
                // 獲取網絡流
                NetworkStream networkStream = client.GetStream();

                // 創建SslStream實例
                using (SslStream sslStream = new SslStream(networkStream, false, ValidateServerCertificate))
                {
                    // 開始SSL/TLS握手
                    sslStream.AuthenticateAsClient(serverAddress, null, SslProtocols.Tls12, true);

                    // 發送數據
                    byte[] message = Encoding.UTF8.GetBytes("GET / HTTP/1.1\r\nHost: example.com\r\nConnection: close\r\n\r\n");
                    sslStream.Write(message);

                    // 接收數據
                    byte[] buffer = new byte[2048];
                    int bytesRead = sslStream.Read(buffer, 0, buffer.Length);

                    // 處理接收到的數據
                    string response = Encoding.UTF8.GetString(buffer, 0, bytesRead);
                    Console.WriteLine(response);
                }
            }
        }

        // 驗證服務器證書的回調函數
        public static bool ValidateServerCertificate(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
        {
            if (sslPolicyErrors == SslPolicyErrors.None)
                return true;

            Console.WriteLine("Certificate error: {0}", sslPolicyErrors);
            return false;
        }
    }
}

這個示例展示了如何使用TcpClient和SslStream類創建一個簡單的客戶端，連接到服務器并進行SSL/TLS加密通信。請注意，這個示例僅用于演示目的，實際應用中可能需要根據具體需求進行修改。