I am having problem in reading serial port data in visual studio 2015

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

namespace ultra
{
    public partial class Form1 : Form
    {
        private SerialPort myport;
        private DateTime date;
        private string in_data;
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            myport = new SerialPort();
            myport.BaudRate = 9600;
            myport.PortName = "COM5";
            myport.Parity = Parity.None;
            myport.DataBits = 8;
            myport.StopBits = StopBits.One;
            myport.DataReceived += myport_DataReceived;
            try
            {
                myport.Open();
                textBox1.Text = "";
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message, "Error");
            }
        }
        void myport_DataReceived(object sender, SerialDataReceivedEventArgs e)
        {
            in_data = myport.ReadLine();
            this.Invoke(new EventHandler(displaydata_event));

        }
        private void displaydata_event(object sender, EventArgs e)
        {
            date = DateTime.Now;
            string time = date.Hour + ";" + date.Minute + ";" + date.Second;
            textBox1.AppendText(time + "\t\t\t\t\t" + in_data);
            label2.Text = in_data;
        }
    }
}