c#winform多线程假死（不能拖动窗口，窗口未响应）（自己用）

修改前

public delegate void treeinvoke(int i);
        public Form1()
        {
            InitializeComponent();
        }
        private void button1_Click(object sender, EventArgs e)
        {
            Console.WriteLine("AAA");
            System.Threading.Thread th = new System.Threading.Thread(new System.Threading.ThreadStart(this.startupdate));
            th.IsBackground = true;
            th.Start();
            Console.WriteLine("BBB");
        }

        private void startupdate()
        {
            Console.WriteLine("CCC");
            this.BeginInvoke(new treeinvoke(this.UpdateTreeView), 0);
            Console.WriteLine("DDD");

        }

        private void UpdateTreeView(int j)
        {

            try
            {
                Console.WriteLine("EEE");
                Thread.Sleep(5000);
                Console.WriteLine("FFF");
            }
            catch (Exception ex)
            {

            }

        }

修改后：

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

namespace test
{
    public partial class Form1 : Form
    {
        public delegate void treeinvoke(int i);
        int num1 = 0;
        int num2 = 10000;
        public Form1()
        {
            InitializeComponent();
        }
        private void button1_Click(object sender, EventArgs e)
        {
            Console.WriteLine("AAA");


            for (int i = 0; i < 5000; i++)
            {
                ThreadPool.QueueUserWorkItem(startupdate, i);
            }

            Console.WriteLine("BBB");
        }
        private delegate void updateui();
        private void TimeEvent(object source, System.Timers.ElapsedEventArgs e)
        {
            this.BeginInvoke(new updateui(upui));
        }
        private void upui()
        {
            label1.Text = num1.ToString() + "/" + num2.ToString();
        }
        private void startupdate(object c)
        {
            System.DateTime dt = DateTime.Now;

            Console.WriteLine("CCC");
            UpdateTreeView(int.Parse(c.ToString()));
            Console.WriteLine("DDD");
        }

        private void UpdateTreeView(int j)
        {
            //反正这里执行耗时间操作Start
            try
            {
                string strPageData = GetHttp("http://news.163.com/rank/", Encoding.GetEncoding("GB2312"));
                this.BeginInvoke(new updateui(upui));//这里更新UI
                Console.WriteLine(j.ToString());
                num1 = j;
            }
            catch (Exception ex)
            {

            }
            //反正这里执行耗时间操作End
        }
        public static string GetHttp(string url, Encoding encode)
        {
            string strResult;
            try
            {
                WebClient client = new WebClient();
                client.Encoding = encode;
                strResult = client.DownloadString(url);
            }
            catch
            {
                strResult = "";
            }
            return strResult;
        }

    }
}