用timer做的电子表还有复制到剪贴板功能

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;


namespace WindowsFormsApplication4
{
    public partial class Form1 : Form
    {
        Label lbl_date = new Label();
        Label lbl_time = new Label();
        TextBox txt_zhuisu = new TextBox();
        Button btn_copy = new Button();
        Timer t = new Timer();

        public Form1()
        {
            InitializeComponent();
            this.StartPosition = FormStartPosition.CenterScreen;

            lbl_date.SetBounds(0, 0, 290, 50);
            lbl_date.Font = new Font("微软雅黑", 20f, FontStyle.Bold);

            lbl_time.SetBounds(0, 60, 290, 50);
            lbl_time.Font = new Font("微软雅黑", 20f, FontStyle.Bold);

            txt_zhuisu.SetBounds(0, 120, 290, 50);
            txt_zhuisu.Font = new Font("微软雅黑", 12f, FontStyle.Bold);
            txt_zhuisu.Text = "追溯码：370000000000000000";
            txt_zhuisu.Enabled = false;
            txt_zhuisu.ReadOnly = true;

            btn_copy.SetBounds(0, 180, 285, 50);
            btn_copy.Text = "点击复制追溯码";

        }



        private void Form1_Load(object sender, EventArgs e)
        {

            btn_copy.Click += b_Click;

            this.Controls.Add(lbl_date);
            this.Controls.Add(lbl_time);
            this.Controls.Add(txt_zhuisu);
            this.Controls.Add(btn_copy);

            t.Interval = 500;
            t.Tick += t_Tick;
            t.Start();
        }

        void b_Click(object sender, EventArgs e)
        {
            Clipboard.SetText("370000000000000000");
        }

        void t_Tick(object sender, EventArgs e)
        {
            this.lbl_date.Text = DateTime.Now.ToLongDateString();
            this.lbl_time.Text = DateTime.Now.ToLongTimeString();
        }
    }
}