asp.net ，要在Global.asax里的protected void Application_Start(object sender, EventArgs e){}里面（应用程序启动时）调用类库里写好的方法去抓取网页的内容更新的数据库，类库代码如下：

WebBrowser webb = new WebBrowser();
            webb.Navigate(url);
            while (webb.ReadyState != WebBrowserReadyState.Complete)
            {
                System.Windows.Forms.Application.DoEvents();
            }
            if (webb != null)
            {
                try
                {
                    reader = new StreamReader(webb.DocumentStream, Encoding.GetEncoding(webb.Document.Encoding));
                    result = reader.ReadToEnd();
                }
                catch
                {
                    return;
                }
                finally
                {
                    reader.Close();
                    webb.Dispose();
                }
            }

可是到WebBrowser webb = new WebBrowser();这一步就出题目上的错误了，试过加上[STAThread]也没用，求解决啊！