TcpClient - TcpListener Testtool C#

Question

Hello,
I am looking for a good example server client.
With reconnection in case of error, both sides.
When I send a request, I want a response in a certain time.

How can I achieve this?

When I close the application everything should close cleanly. However, I am in an infinite loop. What is the best way to do this?

---

Client

namespace Client
{
    public partial class Client : Form
    {
        public Client()
        {
            InitializeComponent();
        }

        TcpClient MyTcpClient = new TcpClient();

        //Declare and Initialize the IP Adress
        IPAddress ipAd = IPAddress.Parse("127.0.0.1");

        //Declare and Initilize the Port Number;
        int PortNumber = 8888;



        private void Client_Load(object sender, EventArgs e)
        {
            Console.WriteLine("Connecting.....");
            try
            {
                MyTcpClient.Connect(ipAd, PortNumber);
                txtStatus.Text += Environment.NewLine + "Connected";
                txtStatus.Text += Environment.NewLine + "Enter the string to be transmitted";
            }
            catch { }
        }

        private void btnSend_Click(object sender, EventArgs e)
        {
            String str = txtEnviar.Text + "$";
            Stream stm = MyTcpClient.GetStream();

            ASCIIEncoding asen = new ASCIIEncoding();
            byte[] ba = asen.GetBytes(str);

            txtStatus.Text += Environment.NewLine + "Transmitting...";
            //Console.WriteLine("Transmitting.....");

            stm.Write(ba, 0, ba.Length);

            byte[] bb = new byte[100];
            int k = stm.Read(bb, 0, 100);   // ** Timeout ? reconnect....

            string Response = Encoding.ASCII.GetString(bb);

            txtStatus.Text += Environment.NewLine + "Response from server: " + Response;

        }       
    }
}

Server

namespace Server
{
    public partial class Server : Form
    {
        public Server()
        {
            InitializeComponent();
        }

        //Declare and Initialize the IP Address
        static IPAddress ipAd = IPAddress.Parse("127.0.0.1");

        //Declare and Initilize the Port Number;
        static int PortNumber = 8888;

        /* Initializes the Listener */
        TcpListener ServerListener = new TcpListener(ipAd, PortNumber);
        TcpClient clientSocket = default(TcpClient);



        private void Server_Load(object sender, EventArgs e)
        {
            Thread ThreadingServer = new Thread(StartServer);
            ThreadingServer.Start();
        }

        private void THREAD_MOD(string teste)
        {
            txtStatus.Text += Environment.NewLine + teste;
        }

        private void StartServer()
        {
            Action<string> DelegateTeste_ModifyText = THREAD_MOD;
            ServerListener.Start();
            Invoke(DelegateTeste_ModifyText, "Server waiting connections!");
            clientSocket = ServerListener.AcceptTcpClient();
            Invoke(DelegateTeste_ModifyText, "Server ready!");

            while (true)     // Operator press close the application or cancel  -- However, I am in an infinite loop. What is the best way to do this?
            {
                try
                {    
                    NetworkStream networkStream = clientSocket.GetStream();
                    byte[] bytesFrom = new byte[20];
                    networkStream.Read(bytesFrom, 0, 20);
                    string dataFromClient = System.Text.Encoding.ASCII.GetString(bytesFrom);
                    dataFromClient = dataFromClient.Substring(0, dataFromClient.IndexOf("$"));

                    Invoke(DelegateTeste_ModifyText, $"From Client: {dataFromClient}  !");


                    string serverResponse = "Received!";
                    Byte[] sendBytes = Encoding.ASCII.GetBytes(serverResponse);
                    networkStream.Write(sendBytes, 0, sendBytes.Length);
                    networkStream.Flush();
                }
                catch
                {
                    ServerListener.Stop();
                    ServerListener.Start();
                    Invoke(DelegateTeste_ModifyText, "Server waiting connections!");
                    clientSocket = ServerListener.AcceptTcpClient();
                    Invoke(DelegateTeste_ModifyText, "Server ready!");
                }

            }
        }

    }
}

Answer 1

@Markus Freitag , based on my test, I reproduced your problem about the app will still be in an infinite loop when you close the server app.

I made some changes on your code about StartServer method, now it could work it well when you connected to client and click the close button.

Server code:

public partial class Form1 : Form  
    {  
        public Form1()  
        {  
            InitializeComponent();  
        }  
        static IPAddress ipAd = IPAddress.Parse("127.0.0.1");  
  
        //Declare and Initilize the Port Number;  
        static int PortNumber = 8888;  
  
        /* Initializes the Listener */  
        TcpListener ServerListener = new TcpListener(ipAd, PortNumber);  
        TcpClient clientSocket = default(TcpClient);  
  
        Thread ThreadingServer;  
        public BinaryReader br;  
        public BinaryWriter bw;  
        private void Form1_Load(object sender, EventArgs e)  
        {  
            ThreadingServer = new Thread(StartServer);  
  
            ThreadingServer.Start();  
        }  
  
        private void THREAD_MOD(string teste)  
        {  
            txtStatus.Text += Environment.NewLine + teste;  
        }  
  
        private void StartServer()  
        {  
            try  
            {  
                Action<string> DelegateTeste_ModifyText = THREAD_MOD;  
                ServerListener.Start();  
                Invoke(DelegateTeste_ModifyText, "Server waiting connections!");  
                clientSocket = ServerListener.AcceptTcpClient();  
                Invoke(DelegateTeste_ModifyText, "Server ready!");  
                while (true)     // Operator press close the application or cancel  -- However, I am in an infinite loop. What is the best way to do this?  
                {  
                    try  
                    {  
                        NetworkStream clientStream = clientSocket.GetStream();  
                        br = new BinaryReader(clientStream);  
                        string receive = null;  
                        receive = br.ReadString();  
                        txtStatus.Invoke((MethodInvoker)delegate { txtStatus.Text += receive; });  
  
                    }  
                    catch  
                    {  
                        if (clientSocket.Connected == false)  
                        {  
                            MessageBox.Show("the connection is closed");  
                        }  
                        else  
                        {  
                            MessageBox.Show(ex.ToString());  
                        }  
                        clientSocket.Close();  
                    }  
                    
                    
                }  
  
            }    
            catch (Exception ex)  
            {  
  
                if (clientSocket.Connected == false)  
                {  
                    MessageBox.Show("the connection is closed");  
                }  
                else  
                {  
                    MessageBox.Show(ex.ToString());  
                }  
                clientSocket.Close();  
  
  
            }  
            finally  
            {  
                ServerListener.Stop();  
            }  
        }  
  
        private void Form1_FormClosed(object sender, FormClosedEventArgs e)  
        {  
            clientSocket.Close();  
  
        }  
    }  

Client code:

public partial class Form1 : Form  
    {  
        public Form1()  
        {  
            InitializeComponent();  
        }  
  
        private TcpClient client;  
        public BinaryReader br;  
        public BinaryWriter bw;  
        private void Form1_Load(object sender, EventArgs e)  
        {  
            Thread myThread = new Thread(ClientA);  
            myThread.Start();  
        }  
  
        private void ClientA()  
        {  
            client = new TcpClient("127.0.0.1", 8888);  
  
            Console.WriteLine("Connected to server");  
            txtStatus.Invoke((MethodInvoker)delegate { txtStatus.Text = "Connected to server"; });  
            while (true)  
            {  
                try  
                {  
                    NetworkStream clientStream = client.GetStream();  
                    br = new BinaryReader(clientStream);  
                    string receive = null;  
                    receive = br.ReadString();  
                    txtEnviar.Invoke((MethodInvoker)delegate { txtEnviar.Text = receive; });  
                      
                }  
                catch  
                {  
                    MessageBox.Show("the server connection is closed！");  
                    break;  
                }  
            }  
        }  
  
        private void button1_Click(object sender, EventArgs e)  
        {  
            NetworkStream clientStream = client.GetStream();  
            bw = new BinaryWriter(clientStream);  
            bw.Write(txtEnviar.Text);  
       
  
  
  
        }  
  
          
             
          
    }  

Best regards,
Jack

---

If the answer is the right solution, please click "Accept Answer" and upvote it.If you have extra questions about this answer, please click "Comment".

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.