比较DoEvents()与refresh()和两个都不使用的效率

用一个循环来验证(100000次),以下是代码.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace WindowsAppDoEvents
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            label1.Text = DateTime.Now.ToLongTimeString() +"  "+ DateTime.Now.Millisecond.ToString();
            for (int q = 0; q < 100000; q++)
            {

                textBox1.Text = q.ToString();
                //Application.DoEvents();//实时响应文本框中的值
            }
            label3.Text = DateTime.Now.ToLongTimeString() + "  " + DateTime.Now.Millisecond.ToString();
        }

        private void button2_Click(object sender, EventArgs e)
        {
            label2.Text = DateTime.Now.ToLongTimeString() + "  " + DateTime.Now.Millisecond.ToString();
            for (int q = 0; q < 100000; q++)
            {

                textBox2.Text = q.ToString();
                Application.DoEvents();//实时响应文本框中的值
                
            }
            label4.Text = DateTime.Now.ToLongTimeString() + "  " + DateTime.Now.Millisecond.ToString();
        }

        private void button3_Click(object sender, EventArgs e)
        {
            label5.Text = DateTime.Now.ToLongTimeString() + "  " + DateTime.Now.Millisecond.ToString();
            for (int q = 0; q < 100000; q++)
            {

                textBox3.Text = q.ToString();
                //Application.DoEvents();//实时响应文本框中的值
                textBox3.Refresh();
            }
            label6.Text = DateTime.Now.ToLongTimeString() + "  " + DateTime.Now.Millisecond.ToString();
        }

    }
}

效果图如下:

第一个用了3875毫秒

第二个用了14078毫秒

第三个用了12000毫秒

效率高低很明显.