多线程

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

namespace 多线程
{
    public partial class Form1 : Form
    {
        private CancellationTokenSource cts;
        public Form1()
        {
            InitializeComponent();
        }
        private void CountTo(int countTo, CancellationToken ct)
        {
            int sum = 0;
            for (; countTo > 0; countTo--)
            {
                if (ct.IsCancellationRequested)
                {
                    break;
                }
                sum += countTo;
                //Invoke方法用于获得创建lbl_Status的线程所在的上下文
                this.Invoke(new Action(() => textBox1.Text = sum.ToString()));
                Thread.Sleep(200);
            }
        }
        private void button1_Click(object sender, EventArgs e)
        {
            cts = new CancellationTokenSource();
            ThreadPool.QueueUserWorkItem(state => CountTo(int.Parse(textBox2.Text), cts.Token));
        }
        private void button2_Click(object sender, EventArgs e)
        {
            if (cts != null)
            {
                cts.Cancel();
            }              
        }
    }
}

多线程解决界面卡顿问题

ThreadPool.QueueUserWorkItem 方法 (WaitCallback)

说明：将方法排入队列以便执行，WaitCallback，表示要执行的方法。如果将方法成功排入队列，则为 true；否则为 false。

示例：addtest方法需要比较长的时间来响应，因此在button1_Click被点击以后，程序会失去响应，使用ThreadPool.QueueUserWorkItem 后，页面会继续响应其他时间，等addtest执行结束后，响应结果。

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

namespace 多线程
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }private void button1_Click(object sender, EventArgs e)
        {
            ThreadPool.QueueUserWorkItem(new WaitCallback(addtest), "Testaa"); 
        }private void addtest(object aa)
        {
            long result = 0;
            for (int i = 0; i < 1000000000; i++)
            {
                result += i;
            }
            textBox1.Text = result.ToString() + "HELLO";
        }
    }
}