Tcpip Listner Problem c# receiving data in shape of three message from device how to combine three message into one or ignor second or third Message and save in to text File

Question

Hi, I am new to programming and creating TCPIP Listner in C# my Tcpip Listner (server ) is attached with the device. When trying to send data from the device. Devise Send Three string

I want to receive string 1 only not string 2 or 3 String. Kindly advise us on how to ignore string 2 or string 3 when the device sends data to TCPip Listener . or

is it possible to combine string 1 + string + and string 3 in one string and save it to a text file.,

any hint or advice appreciatable.

below is my code C#

using System;  
using System.Collections.Generic;  
using System.ComponentModel;  
using System.Data;  
using System.Drawing;  
using System.Linq;  
using System.Text;  
using System.Windows.Forms;  
using System.Net;  
using System.Net.Sockets;  
using System.IO;  
using System.Data.OleDb;  
using System.Configuration;  
using static System.Windows.Forms.VisualStyles.VisualStyleElement;  
  
namespace TCPServer01  
{  
    public partial class Form1 : Form  
    {  
  
          
        TcpListener mTCPListener;  
        TcpClient mTCPClient;  
        byte[] mRx;  
        string mydata;  
          
  
        private List<ClientNode> mlClientSocks;  
        private object connection;  
  
        public Form1()  
        {  
              
            InitializeComponent();  
            mlClientSocks = new List<ClientNode>(2);  
            CheckForIllegalCrossThreadCalls = false;  
              
        }  
  
        IPAddress findMyIPV4Address()  
        {  
            string strThisHostName = string.Empty;  
            IPHostEntry thisHostDNSEntry = null;  
            IPAddress[] allIPsOfThisHost = null;  
            IPAddress ipv4Ret = null;  
  
            try  
            {  
                strThisHostName = System.Net.Dns.GetHostName();  
                thisHostDNSEntry = System.Net.Dns.GetHostEntry(strThisHostName);  
                allIPsOfThisHost = thisHostDNSEntry.AddressList;  
  
                for (int idx = allIPsOfThisHost.Length - 1; idx >= 0; idx--)  
                {  
                    if (allIPsOfThisHost[idx].AddressFamily == AddressFamily.InterNetwork)  
                    {  
                        ipv4Ret = allIPsOfThisHost[idx];  
                        break;  
                    }  
                }  
            }  
            catch (Exception exc)  
            {  
                MessageBox.Show(exc.Message);  
            }  
  
            return ipv4Ret;  
        }  
  
        private void btnStartListening_Click(object sender, EventArgs e)  
        {  
            IPAddress ipaddr;  
            int nPort;  
  
            if (!int.TryParse(tbPort.Text, out nPort))  
            {  
                nPort = 23000;  
            }  
            if (!IPAddress.TryParse(tbIPAddress.Text, out ipaddr))  
            {  
                MessageBox.Show("Invalid IP address supplied.");  
                return;  
            }  
              
            mTCPListener = new TcpListener(ipaddr, nPort);  
  
            mTCPListener.Start();  
            lblServerStatus.Text = "Server Started ";  
             
  
            mTCPListener.BeginAcceptTcpClient(onCompleteAcceptTcpClient, mTCPListener);  
             
  
        }  
  
        void onCompleteAcceptTcpClient(IAsyncResult iar)  
        {  
            TcpListener tcpl = (TcpListener)iar.AsyncState;  
            TcpClient tclient = null;  
            ClientNode cNode = null;  
  
            try  
            {  
                tclient = tcpl.EndAcceptTcpClient(iar);  
  
                printLine("Client Connected...");  
  
                tcpl.BeginAcceptTcpClient(onCompleteAcceptTcpClient, tcpl);  
  
                lock (mlClientSocks)  
                {  
                    mlClientSocks.Add((cNode = new ClientNode(tclient, new byte[1024], new byte[1024], tclient.Client.RemoteEndPoint.ToString())));  
                    lbClients.Items.Add(cNode.ToString());                      
                }  
  
                tclient.GetStream().BeginRead(cNode.Rx, 0, cNode.Rx.Length, onCompleteReadFromTCPClientStream, tclient);  
  
                //mRx = new byte[1024];  
                //mTCPClient.GetStream().BeginRead(mRx, 0, mRx.Length, onCompleteReadFromTCPClientStream, mTCPClient);  
  
  
            }  
            catch (Exception exc)  
            {  
                MessageBox.Show(exc.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);  
            }  
        }  
  
        void onCompleteReadFromTCPClientStream(IAsyncResult iar)  
        {  
            TcpClient tcpc;  
            int nCountReadBytes = 0;  
            string strRecv;  
            ClientNode cn = null;  
  
            try  
            {  
                lock(mlClientSocks)  
                {  
                    tcpc = (TcpClient)iar.AsyncState;  
  
                    cn = mlClientSocks.Find(x => x.strId == tcpc.Client.RemoteEndPoint.ToString());  
  
                    nCountReadBytes = tcpc.GetStream().EndRead(iar);  
  
                    if (nCountReadBytes == 0)// this happens when the client is disconnected  
                    {  
                        MessageBox.Show("Client disconnected.");  
                        mlClientSocks.Remove(cn);  
                        lbClients.Items.Remove(cn.ToString());  
                        return;  
                    }  
  
                    strRecv = Encoding.ASCII.GetString(cn.Rx, 0, nCountReadBytes).Trim();  
                    //strRecv = Encoding.ASCII.GetString(mRx, 0, nCountReadBytes);  
  
                    printLine(DateTime.Now + " - " + cn.ToString() + ": " + strRecv);  
  
                      
  
                    cn.Rx = new byte[1024];  
  
                    tcpc.GetStream().BeginRead(cn.Rx, 0, cn.Rx.Length, onCompleteReadFromTCPClientStream, tcpc);  
                    // Store Data in Text File   
  
                    TextWriter txt = new StreamWriter("C:\\Users\\SAQ\\Desktop\\demo.txt", append:true);  
                    txt.Write("\n" + strRecv );  
                    txt.Close();  
  
                                        
  
                    // Database Connection  
                   OleDbConnection connection = new OleDbConnection();  
                   connection.ConnectionString = @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source= C:\mydat.accdb";  
                    
                    var datain = strRecv;  
                    datain = datain.Replace("*", "0");  
                    datain =   datain.Substring(0, 174);  
                    //string result = str.Substring(0, 170);  
  
                   
  
  
                    //  Database Connection   
  
                     OleDbCommand cmd1 = new OleDbCommand();  
                     connection.ConnectionString = @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source= C:\mydat.accdb";  
                     mydata = strRecv.Replace("\n", "");  
  
  
                     connection.Open();  
  
                     cmd1.Connection = connection;  
                     cmd1.CommandText = "insert into tbl_Message(Message) values ('" + mydata + "' )";  
                     cmd1.ExecuteNonQuery();  
                     connection.Close();  
  
                      
                                         
                }  
  
  
            }  
            catch (Exception ex)  
            {  
                MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);  
  
                lock (mlClientSocks)  
                {  
                    printLine("Client disconnected: " + cn.ToString());  
                    mlClientSocks.Remove(cn);  
                    lbClients.Items.Remove(cn.ToString());  
                }  
  
            }  
        }  
  
          
  
        public void printLine(string _strPrint)  
        {  
            tbConsoleOutput.Invoke(new Action<string>(doInvoke), _strPrint);  
        }  
  
        public void doInvoke(string _strPrint)  
        {  
            tbConsoleOutput.Text = _strPrint + Environment.NewLine + tbConsoleOutput.Text;  
        }  
  
        private void btnSend_Click(object sender, EventArgs e)  
        {  
            if (lbClients.Items.Count <= 0) return;  
            if (string.IsNullOrEmpty(tbPayload.Text)) return;  
  
            ClientNode cn = null;  
  
            lock(mlClientSocks)  
            {  
                cn = mlClientSocks.Find(x => x.strId == lbClients.SelectedItem.ToString());  
                cn.Tx = new byte[512];  
  
                try  
                {  
                    if (cn != null)  
                    {  
                        if (cn.tclient!= null)  
                        {  
                            if (cn.tclient.Client.Connected)  
                            {  
                                cn.Tx = Encoding.ASCII.GetBytes(tbPayload.Text);  
                                cn.tclient.GetStream().BeginWrite(cn.Tx, 0, cn.Tx.Length, onCompleteWriteToClientStream, cn.tclient);  
                            }  
                        }  
                    }  
                }  
                catch (Exception exc)  
                {  
                    MessageBox.Show(exc.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);  
                }  
            }  
        }  
  
        private void onCompleteWriteToClientStream(IAsyncResult iar)  
        {  
            try  
            {  
                TcpClient tcpc = (TcpClient)iar.AsyncState;  
                tcpc.GetStream().EndWrite(iar);  
            }  
            catch (Exception exc)  
            {  
                MessageBox.Show(exc.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);  
            }  
        }  
  
        private void btnFindIPv4IP_Click(object sender, EventArgs e)  
        {  
            IPAddress ipa = null;  
            ipa = findMyIPV4Address();  
  
            if (ipa != null)  
            {  
                tbIPAddress.Text = ipa.ToString();  
            }  
        }  
  
        private void btnFindIPv4IP_Click_1(object sender, EventArgs e)  
        {  
            IPAddress ipa = null;  
  
            ipa = findMyIPV4Address();  
            if (ipa != null)  
            {  
                tbIPAddress.Text = ipa.ToString();  
            }  
        }  
  
             
          
  
        private void btnServerStop_Click(object sender, EventArgs e)  
        {  
            mTCPListener.Start();  
  
            lblServerStatus.Text = "Server Stop ";  
        }  
    }  
}