线程中webBrowser1_DocumentCompleted不执行的问题

这是入口
   public void run( )
        {
            WebBrowser  webBrowser1 = new WebBrowser();            webBrowser1.Name = Thread.CurrentThread.ManagedThreadId.ToString();
            webBrowser1.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(webBrowser1_DocumentCompleted);
            s = generate(5);
            Random r = new Random();
            int ia = r.Next(0, 5);
            string   address =  straddress[ia];
            //if (address != String.Empty)
            //{
            //    RefreshIESettings(address);
            //}            try
            {
                while (ii < 1)
                {
                    webBrowser1.Navigate("http://www.baidu.com", null, null, null);
                   // Thread.Sleep(10000);
                    //System.Console.WriteLine(ii.ToString() + s + webBrowser1.Name + address + webBrowser1.Url.ToString());
                    Thread.Sleep(15000);
                    ii += 1;                }
            }
            catch (Exception ex)
            {
                System.Console.WriteLine("run:" + ex.Message);
            }
这是winform中的代码   private void button4_Click(object sender, EventArgs e)
        {
            for (int i = 0; i < 10; i++)
            {
                Class1 gooo = new Class1();
                System.Threading.Thread s = new System.Threading.Thread(new System.Threading.ThreadStart(gooo.run ));
                s.SetApartmentState(System.Threading.ApartmentState.STA);                s.Start();
                     }
        }