倒计时10秒

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;

namespace _08
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            label2.ForeColor = Color.Black;
            label2.Text = "" + i;
            timer1.Interval = 1000;
        }
        int i = 10;
        private void timer1_Tick(object sender, EventArgs e)
        {
            if (i <= 4)
            {
                label2.ForeColor = Color.Red;
            }
            if (i > 0)
            {
                i--;
                label2.Text = "" + i;
            }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            if (timer1.Enabled == true)
            {
                timer1.Stop();
            }
            else
            {
                timer1.Start();
            }
        }

        private void button2_Click(object sender, EventArgs e)
        {
            i = 10;
            label2.Text = "" + i;
            timer1.Stop();
        }
    }
}