C#抓取网页

if (webBrowser1.ReadyState == WebBrowserReadyState.Complete && webBrowser1.IsBusy == false)
            {
                //panelEx1.Text = "页面加载完成";
                timer1.Enabled = false;
            }

加载完毕事件

this.webBrowser1.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(webBrowser1_DocumentCompleted);

void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
        {
            Trace.WriteLine(e.Url);
            currentUrl=e.Url.ToString();
            if (currentUrl == "https://dynamic.12306.cn/otsweb/")
            {
                this.webBrowser1.Navigate("https://dynamic.12306.cn/otsweb/order/querySingleAction.do?method=init", "main");
            }
            
        }

 HttpWebRequest取页面文本信息

WebRequest req = WebRequest.Create(url);
            WebResponse res = req.GetResponse();
            Stream str = res.GetResponseStream();
            StreamReader sr = new StreamReader(str, Encoding.UTF8);

            string html = sr.ReadToEnd();
            sr.Close();
            res.Close();

HtmlElement类的实例里面要获得class属性的值需要GetAttribute("className")，因为class和C#的关键字重名了。