C# Winfrom 简单的运用Timer控件

注意，在使用DateAndTime时，需要添加引用 using Microsoft.VisualBasic;否则不可以计算时间之间的差值。

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 Microsoft.VisualBasic;

namespace DJS {

    public partial class Form1 : Form {

        DateTime dtNow, dtSet;

        public Form1() {

            InitializeComponent();

        }

        private void button1_Click(object sender, EventArgs e) {

            if(button1.Text=="设置") {

                button1.Text = "停止";

                timer2.Start();

            }

            else if(button1.Text=="停止") {

                button1.Text = "设置";

                timer2.Stop();

                label7.Text = "倒计时已取消";

            }

        }

        private void timer1_Tick(object sender, EventArgs e) {

            label2.Text = DateTime.Now.ToLongTimeString();//显示系统时间

            dtNow = Convert.ToDateTime(label2.Text);

        }

        private void timer2_Tick(object sender, EventArgs e) {

            //记录设置的到期时间

            dtSet = Convert.ToDateTime(numericUpDown1.Value + ":" + numericUpDown2.Value + ":" + numericUpDown3.Value);

            long countdown = DateAndTime.DateDiff(DateInterval.Second, dtNow, dtSet, FirstDayOfWeek.Monday, FirstWeekOfYear.FirstFourDays);

            if(countdown>) {  //判断倒计时是否大于0

                label7.Text="倒计时已设置，剩余"+ countdown + "秒";

            }

            else {

                label7.Text = "倒计时已到";

            }

        }

        private void Form1_Load(object sender, EventArgs e) {

            timer1.Interval = ;

            timer1.Enabled = true;

            numericUpDown1.Value = DateTime.Now.Hour;

            numericUpDown2.Value = DateTime.Now.Minute;

            numericUpDown3.Value = DateTime.Now.Second;

        }

    }

}

Timer控件又称为计时器组件，可以定期引发事件，时间的间隔的长度用interval属性定义，其属性值为毫秒为单位，每个时间间隔会自动触发tick事件，开发人员可以在tick事件中添加要执行操作的代码