C#中使用TCP通信

TCP通信需要通信雙方都在線，所以需要先啟動服務端進行監聽，客戶端才能獲得連接，服務端代碼：

 static void Main(string[] args)
        {
            TcpClient client = null;
            NetworkStream stream = null;
            byte[] buffer = null;
            string receiveString = null;

            IPAddress localIP = IPAddress.Parse("127.0.0.1");
            int localPort = 11000;
            TcpListener listener = new TcpListener(localIP, localPort);//用本地IP和端口實例化Listener
            listener.Start();//開始監聽
            while (true)
            {
                client = listener.AcceptTcpClient();//接受一個Client
                buffer = new byte[client.ReceiveBufferSize];
                stream = client.GetStream();//獲取網絡流
                stream.Read(buffer, 0, buffer.Length);//讀取網絡流中的數據
                stream.Close();//關閉流
                client.Close();//關閉Client

                receiveString = Encoding.Default.GetString(buffer).Trim('\0');//轉換成字符串
                Console.WriteLine(receiveString);
            }
        }

只有服務端開啟監聽後，客戶端才能正確連接，所以服務端要一直開啟監聽，客戶端每次發送數據，都要首先與服務端建立連接，連接建立完成後才進行數據發送。客戶端代碼：

static void Main(string[] args)
        {
            string sendString = null;//要發送的字符串
            byte[] sendData = null;//要發送的字節數組
            TcpClient client = null;//TcpClient實例
            NetworkStream stream = null;//網絡流

            IPAddress remoteIP = IPAddress.Parse("127.0.0.1");//遠程主機IP
            int remotePort = 11000;//遠程主機端口

            while (true)//死循環
            {
                sendString = Console.ReadLine();//獲取要發送的字符串
                sendData = Encoding.Default.GetBytes(sendString);//獲取要發送的字節數組
                client = new TcpClient();//實例化TcpClient
                try
                {
                    client.Connect(remoteIP, remotePort);//連接遠程主機
                }
                catch (System.Exception ex)
                {
                    Console.WriteLine("連接超時，服務器沒有響應！");//連接失敗
                    Console.ReadKey();
                    return;
                }
                stream = client.GetStream();//獲取網絡流
                stream.Write(sendData, 0, sendData.Length);//將數據寫入網絡流
                stream.Close();//關閉網絡流
                client.Close();//關閉客戶端
            }
        }