求救！用HtmlElement来模拟事件（InvokeMember）不成功，为何？？？

       private void getData()

        {

            HtmlDocument doc = webBrowser1.Document;

             。。。。。

       System.Timers.Timer timer = null;



        private void Form1_Load(object sender, EventArgs e)

        {

            string url = "http://stock.finance.sina.com.cn/hkstock/finance/01398.html";



            webBrowser1.Navigate(url);

            timer = new System.Timers.Timer(1000);

            timer.AutoReset = false;

            timer.Elapsed += new System.Timers.ElapsedEventHandler(Timer_Elapsed);

            

        }



        public delegate void GetDataHandler();



        private void Timer_Elapsed(object sender, ElapsedEventArgs e)

        {

            Invoke(new GetDataHandler(getData));



            timer.Start();

        }





         private void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)

        {

            //避免webbroswer.DocumentCompleted被多次引发

            if ((e.Url != webBrowser1.Url) || (webBrowser1.ReadyState != WebBrowserReadyState.Complete))

                return;

            //下面写你要在页面加载完毕后执行的代码。



            getSelectedCtrl();

        }



        private void getSelectedCtrl()

        {

            System.Windows.Forms.HtmlDocument doc = this.webBrowser1.Document;

            System.Windows.Forms.HtmlElementCollection selectCtrls = doc.GetElementsByTagName("select");

            string attName;



            foreach (System.Windows.Forms.HtmlElement selectCtrl in selectCtrls)

            {

                attName = selectCtrl.GetAttribute("table");

                if (attName.Equals("tableGetBalanceSheet"))//如果table属性是资产负债表的话,模拟引发“报表类型”的选择控件

                {

                    foreach(HtmlElement option in selectCtrl.Children)

                    {

                        if(option.GetAttribute("value") == "zero")

                        {

                            option.SetAttribute("selected", "selected");

                            break;

                        }

                    }

                    selectCtrl.RaiseEvent("onchange");

                    timer.Start();

                    return;



                }



            }



        }

private void getSelectedCtrl()

        {

            System.Windows.Forms.HtmlDocument doc = this.webBrowser1.Document;

            System.Windows.Forms.HtmlElementCollection selectCtrls = doc.GetElementsByTagName("select");

            string attName;



            foreach (System.Windows.Forms.HtmlElement selectCtrl in selectCtrls)

            {

                attName = selectCtrl.GetAttribute("table");

                if (attName.Equals("tableGetBalanceSheet"))//如果table属性是资产负债表的话,模拟引发“报表类型”的选择控件

                {

                    //this.richTextBox1.Text = selectCtrl.InnerText;

                    // 准备参数.

                    //Object[] args = new Object[1];

                    //args[0] = (Object)"zero"; //zero代表报表类型为“年报”

                    //selectCtrl.InvokeMember("onchange",args);

                    //return;



                    foreach (HtmlElement option in selectCtrl.Children)

                    {

                        if (option.GetAttribute("value") == "zero")

                        {

                            option.SetAttribute("selected", "selected");

                            break;

                        }

                    }

                    selectCtrl.RaiseEvent("onchange");





                    



                    timer1.Interval = 5000; //5秒间隔

                    timer1.Start(); // 计时开始

                                      



                    getData(selectCtrl.Document);//引发事件成功后抓取数据

                    return;



                

                }

            

            }

           



        

        }



        private void timer1_Tick(object sender, EventArgs e)

        {

            timer1.Stop();



        }

        private void getSelectedCtrl()

        {

            System.Windows.Forms.HtmlDocument doc = this.webBrowser1.Document;

            System.Windows.Forms.HtmlElementCollection selectCtrls = doc.GetElementsByTagName("select");

            string attName;



            foreach (System.Windows.Forms.HtmlElement selectCtrl in selectCtrls)

            {

                attName = selectCtrl.GetAttribute("table");

                if (attName.Equals("tableGetBalanceSheet"))//如果table属性是资产负债表的话,模拟引发“报表类型”的选择控件

                {

                    //调试过，已经成功进入了该条件语句

                    // 准备参数.

                    //Object[] args = new Object[1];

                    //args[0] = (Object)"zero"; //zero代表报表类型为“年报”

                    //selectCtrl.InvokeMember("onchange", args);

                    foreach(HtmlElement option in selectCtrl.Children)

                    {

                        if(option.GetAttribute("value") == "zero")

                        {

                            option.SetAttribute("selected", "selected");

                            break;

                        }

                    }

                    selectCtrl.RaiseEvent("onchange");

                    return;



                }



            }



        }

 private void getSelectedCtrl()

        {

            System.Windows.Forms.HtmlDocument doc = this.webBrowser1.Document;

            System.Windows.Forms.HtmlElementCollection selectCtrls = doc.GetElementsByTagName("select");

            string attName;



            foreach (System.Windows.Forms.HtmlElement selectCtrl in selectCtrls)

            {

                attName = selectCtrl.GetAttribute("table");

                if (attName.Equals("tableGetBalanceSheet"))//如果table属性是资产负债表的话,模拟引发“报表类型”的选择控件

                {

                    //this.richTextBox1.Text = selectCtrl.InnerText;

                    // 准备参数.

                    //Object[] args = new Object[1];

                    //args[0] = (Object)"zero"; //zero代表报表类型为“年报”

                    //selectCtrl.InvokeMember("onchange",args);

                    //return;



                    foreach (HtmlElement option in selectCtrl.Children)

                    {

                        if (option.GetAttribute("value") == "zero")

                        {

                            option.SetAttribute("selected", "selected");

                            break;

                        }

                    }

                    selectCtrl.RaiseEvent("onchange");

                    getData(doc);//引发事件成功后抓取数据

                    return;



                

                }

            

            }

           



        

        }





 private void getData(HtmlDocument doc)

        {





            StringBuilder str = new StringBuilder();

           



            //System.Windows.Forms.HtmlDocument doc = this.webBrowser1.Document;

            System.Windows.Forms.HtmlElement table = doc.GetElementById("tableGetBalanceSheet");//获取资产负债表

            System.Windows.Forms.HtmlElementCollection trs;//行的集合

            System.Windows.Forms.HtmlElementCollection ths;//项目的集合

            System.Windows.Forms.HtmlElementCollection tds;//单元格的集合

            int i = 0;//用于行的计数

            int j = 0;//用于单元格的计数

            int k = 0;//用于年报单元格的计数

            this.dataGridView1.Rows.Clear();//清除表的所有行

            this.dataGridView1.Columns.Clear();//清除表的列



                    //获取行集合并遍历之

                    trs = table.GetElementsByTagName("tr");

                    foreach (System.Windows.Forms.HtmlElement tr in trs)

                    {

                        i++;



                        //获取项目列的单元格集合并遍历之

                        ths = tr.GetElementsByTagName("th");                        

                        foreach (System.Windows.Forms.HtmlElement th in ths)

                        {

                            k++;

                            if (i == 1)

                            {

                                this.dataGridView1.Columns.Add(th.InnerText, th.InnerText);//添加项目列

                               

                            }



                            this.dataGridView1.Rows.Add();

                            this.dataGridView1.Rows[this.dataGridView1.Rows.Count-2].Cells[0].Value=th.InnerText;//填充项目数据



                        

                        }



                        //获取普通数据列的单元格并遍历之

                        tds = tr.GetElementsByTagName("td");

                        j = 0;

                        foreach (System.Windows.Forms.HtmlElement td in tds)

                        {

                            j++;



                            str.Append(td.InnerText + " ");



                            if (i == 1)

                            {

                                this.dataGridView1.Columns.Add(td.InnerText, td.InnerText);//添加普通列

                                

                            }

                            this.dataGridView1.Rows[this.dataGridView1.Rows.Count - 2].Cells[j].Value = td.InnerText;//填充财务数据





                        }

                        str.Append("\n");







                    }







            this.richTextBox1.Text = str.ToString();

           

           



        

        

        }