Timer进行定时界面处理

一、System.Threading.Timer 与System.Windows.Forms.Timer

    System.Threading.Timer 是一个简单的轻量计时器，它使用回调方法并由线程池线程提供服务。不建议将其用于 Windows 窗体，因为其回调不在用户界面线程上进行（硬要使用的话只能通过委托的方式进行操作界面元素处理）。

    System.Windows.Forms.Timer 是用于 Windows 窗体的更佳选择。要获取基于服务器的计时器功能，可以考虑使用 System.Timers.Timer，它可以引发事件并具有其他功能。

 

二、案例测试说明

1、现需要在界面实现一个倒计时功能。效果如下：

图1

案例代码：

 

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;
using System.Threading;

namespace CountDownCase
{
    public partial class Form1 : Form
    {
        public delegate void DelegateSetControls(Object state);
        public int timeCount = 10;
        public System.Windows.Forms.Timer timer2;

        public Form1()
        {
            InitializeComponent();
            timer2 = new System.Windows.Forms.Timer();
            /*     This sentence can't be used many times.  */
            timer2.Tick += new EventHandler(TimerEventProcessor);
        }

        /*********************---------------------------------------------------------------------------------------------------------------
        *                                                                               Related operation of timer1
        *-------------------------------------------------------------------------------------------------------------------*****************/
        private void timer1_Tick(object sender, EventArgs e)
        {
            this.label1.Text = "CountDown Beginning......";
            if (timeCount != 0)
            {
                this.label2.Text = timeCount.ToString() + "Second";
                timeCount--;
            }
            else
            {
                this.label2.Text = "0 Second";
                this.label1.Text = "The countdown is over......";
                timer1.Stop();
            }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            timeCount = 10;
            timer1.Start();
        }

        /*********************------------------------------------------------------------------------------------------------------------------
        *                                                                               related operation of timer2
        *-------------------------------------------------------------------------------------------------------------------********************/
        public int timeCountTimer2 = 10;
        private void TimerEventProcessor(Object myObject, EventArgs myEventArgs)
        {
            if (timeCountTimer2 != 0)
            {
                this.label3.Text = timeCountTimer2.ToString() + "second";
                timeCountTimer2--;
            }
            else
            {
                this.label3.Text = "0 second";
                this.label4.Text = "Ready for operation......";
                this.timer2.Stop();
            }
        }

        private void button2_Click(object sender, EventArgs e)
        {
            timeCountTimer2 = 10;
            this.timer2.Interval = 1000;
            this.timer2.Start();
            this.label4.Text = "CountDown has begun......";
        }

    }
}

CountDownCase.zip

2、关键代码分析

窗体控件法使用Timer的步骤：

（1）、拖控件

（2）、设置Timer的几个属性

图2

（3）、编写timer的Tick事件

图3

private void timer1_Tick(object sender, EventArgs e)
{
    this.label1.Text = "CountDown Beginning......";
    if (timeCount != 0)
    {
        this.label2.Text = timeCount.ToString() + "Second";
        timeCount--;
    }
    else
    {
        this.label2.Text = "0 Second";
        this.label1.Text = "The countdown is over......";
        timer1.Stop();
    }
}

代码法创建Timer的步骤麻烦些：

（1）、创建好对象

timer2 = new System.Windows.Forms.Timer();

（2）、编写Tick事件委托函数并赋值

timer2.Tick += new EventHandler(TimerEventProcessor);

private void TimerEventProcessor(Object myObject, EventArgs myEventArgs)
{
    if (timeCountTimer2 != 0)
    {
        this.label3.Text = timeCountTimer2.ToString() + "second";
        timeCountTimer2--;
    }
    else
    {
        this.label3.Text = "0 second";
        this.label4.Text = "Ready for operation......";
        this.timer2.Stop();
    }
}

（3）、设置定时触发时钟的时间

this.timer2.Interval = 1000;
this.timer2.Start();

 

OVER!