C#, this.textBox1.AppendText not executed, different thread?

Question

C++ / C#

Good afternoon!
I encountered such a problem, when the event is triggered, the form element:
this.textBox1.AppendText(m + Environment.NewLine);
Does not do anything, more precisely, does not display the variable m on the form , although it contains a string value during step-by-step verification, but its result is not displayed.
Now the essence of the code:

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.IO;
using System.IO.Ports;

//делегат для работы с событием
delegate void MessageDelegate();
namespace testGenerator
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            //получаем все порты доступные в системе
            string[] ports = SerialPort.GetPortNames();
            //очищаем бокс
            comboBox1.Items.Clear();
            //добавляем в comboBox  все найденные порты для выбора
            comboBox1.Items.AddRange(ports);
        }
//функция вывода сообщения полученного из COM  порта
public void writeTB1(string m)
        {
            this.textBox1.AppendText(m + Environment.NewLine);
        }
 //инициализация нужного порта
        private void button2_Click(object sender, EventArgs e)
        {
            var port = new MySerialPort();
            port.Open(comboBox1.SelectedItem.ToString());
        }

//тут пойдет взаимодейсвие с com портом
    public class MySerialPort : SerialPort
    {
        private int _stepIndex;
        private bool _startRead;

        public MySerialPort()
            :base()
        {

            //base.PortName = port;
            base.BaudRate = 9600;
            base.DataBits = 8;
            base.StopBits = StopBits.One;
            base.ReadTimeout = 1000;

            //Подписываемся на событие прихода данных в com  порт
            base.DataReceived += new SerialDataReceivedEventHandler(MySerialPort_DataReceived);
 
        }

        public void Open(string portName)
        {
            if (base.IsOpen)
            {
                base.Close();
            }
            base.PortName = portName;
            base.Open();
        }
//событие прихода данных в буфер com порта
        void MySerialPort_DataReceived(object sender, SerialDataReceivedEventArgs e)
        {
            EventAnswer eventAnswer = new EventAnswer();
            AnswerCsw answerCsw = new AnswerCsw();
            eventAnswer.Send += new MessageDelegate(answerCsw.AnswerEvent);
            var port = (SerialPort)sender;
            try
            {
                int buferSize = port.BytesToRead;
                byte[] _buffer = new byte[buferSize];
                _stepIndex = 0;
                for ( int i=0; i < buferSize; i++)
                {
                    byte bufferReadBt = (byte)port.ReadByte();
                    _buffer[_stepIndex] = bufferReadBt;
                    ++_stepIndex;
                    char rbt = Convert.ToChar(bufferReadBt);
                    //Запись полученного текста в переменную text класса answer
                    AnswerCsw.AnswerText += Convert.ToString(rbt);
//если мы собрали все байты из буфера COM порта то вызываем событие DoEvent();
                    if (_stepIndex == buferSize)
                    {
                        eventAnswer.DoEvent();
                        AnswerCsw.AnswerText = null;
                    }
                }
            }
            catch { }
        }
    }

    //класс для ответа
    class AnswerCsw : Form1
    {
//сюда складываются конвертированные байтики из порта
        public static string AnswerText;
//ну и собственно по приходу события сама функция которая должна отправить собранную
//строку в необходимый мне textbox
        public void AnswerEvent()
        {
            writeTB1(AnswerText);
        }

    }
//событие для отправки ответа, когда все байты уложенны в AnswerText
    class EventAnswer
    {
        public event MessageDelegate Send;
        public void DoEvent()
        {
            Send();
        }
    }
}

I can not understand where the skis do not go.
I initialize the listening port.
I send a command to the com port from another software, the data arrival event is triggered.
Then everything goes perfectly, all bytes are converted and, in order of arrival, are added to the AnswerText: As soon as it reaches the last index, an event is called:
public static string AnswerText;

if (_stepIndex == buferSize)
                    {
                        eventAnswer.DoEvent();
                        AnswerCsw.AnswerText = null;
                    }

Its handler is called:

class EventAnswer
    {
        public event MessageDelegate Send;
        public void DoEvent()
        {
            Send();
        }
    }

because it is subscribed to the Send() event;

eventAnswer.Send += new MessageDelegate(answerCsw.AnswerEvent);

The public void AnswerEvent() function is executed next :

class AnswerCsw : Form1
    {
//сюда складываются конвертированные байтики из порта
        public static string AnswerText;
//ну и собственно по приходу события сама функция которая должна отправить собранную
//строку в необходимый мне textbox
        public void AnswerEvent()
        {
            writeTB1(AnswerText);
        }
    }

Which in turn executes the code:

public void writeTB1(string m)
        {
            this.textBox1.AppendText(m + Environment.NewLine);
        }

But nothing happens, the form still has a white sheet, although I repeat during the step-by-step verification, the m variable contains the text "CC;"
Where did I take a wrong turn? :)
I would be grateful for any answers, scolding for incorrect work with the code is welcome :)

Answer 1

You have a bad application architecture.
Let me explain and then give an example.
1) MySerialPort must emit events.
2) The main window where this object is created must subscribe to the event. (In principle, anyone can subscribe, but in your case it is the main window)
3) When the necessary data is received, the MySerialPort class must send an event.
4) The main window received the data and displayed it on the screen.
Now how to do it:
In a separate file

DataCompleadEventArgs.cs

describe the event class:

namespace MyNamespace
{ 
      public delegate void DataCompleadEventHandler(object sender, DataCompleadEventArgs e);
      public class DataCompleadEventArgs : EventArgs
      {
            private string _data;
 	    public DeviceEventArgs (string data)
 	    {
       	          _data; = data
 	    }
 	    public string Data
 	    {
                  get { return _data; }
 	    }
      }
}

next in class

MySerialPort

write the following:

public class MySerialPort : SerialPort
{
      //  ваш код ...
      //  обьявляете событие
      public event DataCompleadEventHandler DataComplead;
      //  описываете функцию, чтоб слать событие наружу
      private void OnDataComplead(string message)
      {
            if (DataComplead != null) 
            {
                 DataComplead(this, new DataCompleadEventArgs(message));
            }
      }

      public MySerialPort() :base()
      {
            // ваш код ...
            base.DataReceived += new SerialDataReceivedEventHandler(MySerialPort_DataReceived);
      }

      void MySerialPort_DataReceived(object sender, SerialDataReceivedEventArgs e)
      {
            // то, что тут было написано не нужно !!!
            var port = (SerialPort)sender;
            try
            {
                  // ваш код ...
                  var message = Convert.ToString(rbt);
                  if (_stepIndex == buferSize)
                  {
                        // шлём событие наружу 
                        OnDataComplead(message );
                  }
            }
            catch { }
      }
}

And most importantly, in the main window:

public partial class Form1 : Form
{
      public Form1()
      {
            InitializeComponent();
            // ...
      }

      private void button2_Click(object sender, EventArgs e)
      {
            var port = new MySerialPort();
            // подписиваемся на событие
            port.DataComplead += OnDataCompleated;
            port.Open(comboBox1.SelectedItem.ToString());
      }

      private void OnDataCompleated(object sender, DataCompleadEventArgs e)
      {
            // получаем нужные данные
            var message = e.Data;
            writeTB1(message);
      }
}

That's all.

Answer 2

Answer to a similar question

Answer 3

you can try wrapping it in a MethodInvoker, it helps me in 99% of cases
BeginInvoke(new MethodInvoker(delegate
{
textBox1.AppendText("The program has completed its work!");
//this can be any code
}));