C#

I have tried the suggestions found here and elsewhere but still no joy!

DataTable dataTable = new DataTable();

      foreach (DataGridViewColumn col in dataGridView1.Columns)
      {
          dataTable.Columns.Add(col.Name);
      }

      foreach (DataGridViewRow row in dataGridView1.Rows)
      {
          DataRow drow = dataTable.NewRow();
          foreach (DataGridViewCell cell in row.Cells)
          {
              drow[cell.OwningColumn.Name] = cell.Value;
          }
            // The drow (DataRow) has all the Data in its ItemArray property but it does not get saved into the datatable row.
              dataTable.ImportRow(drow); // dataTable.Rows.Add(drow);
              dataTable.AcceptChanges();
            //The columns load but the data rows do not add or import

      }

TextWriter writer = new StreamWriter(FilePathName);

if (dataGridView1.SelectedRows.Count != 0)
{
    foreach (DataGridViewRow row in dataGridView1.SelectedRows)
    {
        for (int i = dataGridView1.Rows(row.Index); i++)
            {
            for (int j = 0; j < dataGridView1.Columns.Count; j++)
            {
                if (j == dataGridView1.Columns.Count - 1)
                {
                    writer.Write("\t" + dataGridView1.Rows[i].Cells[j].Value.ToString());
                }
                else
                    writer.Write("\t" + dataGridView1.Rows[i].Cells[j].Value.ToString() + "\t" + "|");
            }

            writer.WriteLine("");
        }
    }
writer.Close();

if (jb_serial_read == "jb_ready")
           {
               MessageBox.Show("it work");
           }

using System;
using System.IO.Ports;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace kp71
{
    internal class Ai
    {
        private string jb_serial_read;
        private SerialPort Jb_serial;

        public void Start_comunication_with_jbhid()
        {
            Jb_serial = new SerialPort("COM3", 9600)
            {
                ReadTimeout = 1000,
                WriteTimeout = 1000,
                Encoding = Encoding.GetEncoding("iso-8859-1")
            };
            Jb_serial.DataReceived += Jb_serial_DataReceived;
            Jb_serial.Open();
        }
        public void Help_enable()
        {
           if (jb_serial_read == "ok")
            {
                MessageBox.Show("it work");
            }


        }

        private void Jb_serial_DataReceived(object sender, SerialDataReceivedEventArgs e)
        {
            Task jb_hid = new Task(() =>
            {
                try
                {
                    SerialPort sp = (SerialPort)sender;
                    jb_serial_read = Jb_serial.ReadExisting();
                }
                catch (Exception Error)
                {
                }
            });
            jb_hid.Start();
        }
        private void Send_data(string jb_serial_write)
        {
            Jb_serial.WriteLine(jb_serial_write);
        }
    }
}

#include <SoftwareSerial.h>
#include <EEPROM.h>
SoftwareSerial mySerial(10, 11);

// Global digital reserved posts
#define cts 6
#define Watter_pump 7
#define Food_pump 8
#define Alarm 9

// Global analog reserved posts
#define EMG A7;

// CMD
String Command;
String Value;
String cmd;

void setup() {
  // Setup digital pinmode
  pinMode(Alarm, OUTPUT);
  pinMode(Food_pump, OUTPUT);
  pinMode(Watter_pump, OUTPUT);
  pinMode(cts, INPUT);

  // Serial budrate setup
  Serial.begin(9600);
  mySerial.begin(9600);

  // Default start string for pc
  Serial.println("jbHID ready...");
}

void loop() {
  get_cmd();
  Serial.println("jb_ready");
  delay(900);
}

public  void DataReceivedHandler(object sender, SerialDataReceivedEventArgs e)
{
    string indata = port.ReadExisting();
    TextBoxUpdate(indata);
}