using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.IO.Ports ;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void richTextBox1_TextChanged(object sender, EventArgs e)
        {

        }

        private void button1_Click(object sender, EventArgs e)
        {
            button1.BackColor = Color.GreenYellow;

            if (!serialPort1.IsOpen)
                serialPort1.Open();
            textBox1.Text = "Opened";
            this.BackColor = Color.Green;
            serialPort1.DataReceived += new SerialDataReceivedEventHandler(DataReceivedHandler);

        }
        string w;
        private void DataReceivedHandler(object sender, SerialDataReceivedEventArgs e)
        {
            //int numberOfBytesToRead;
            w = serialPort1.ReadLine();
           /// w = serialPort1.ReadTo("SS");
          
            if (w != string.Empty)
            {
             Invoke(new Action(() => richTextBox1.AppendText(w)));
             
  
                ; 

            }
        }

        private void button2_Click(object sender, EventArgs e)
        {
            serialPort1.Close();
            textBox1.Text = "Closed";
        }

        private void label2_Click(object sender, EventArgs e)
        {

        }
    }
}

uart1_write_text("IRAQ\r\n");

serialPort1.DataReceived += new SerialDataReceivedEventHandler(DataReceivedHandler);

 private void DataReceivedHandler(object sender, SerialDataReceivedEventArgs e)
        {
            //int numberOfBytesToRead;
            w = serialPort1.ReadLine();
           /// w = serialPort1.ReadTo("SS");
          
            if (w != string.Empty)
            {
             Invoke(new Action(() => richTextBox1.AppendText(w)));
             
  
                ; 

            }
        }