Web浏览器控件无法正常工作

Question

我将在下面发布我的代码。我有一个带有Web浏览器组件的表单。它被命名为webBrowser1。出于某种疯狂的原因，我在调试模式下运行它，并在System.Threading.Thread.Sleep（2000）中设置了一个断点;它之前的代码似乎根本没有运行。该程序的基本思想是登录网站，搜索部件号，然后返回部件号描述。为什么会这样？有两个按钮，登录按钮和注销按钮。注销是按钮2，登录是按钮1。

  public partial class Form1 : Form
{
     HtmlElementCollection firstPage;
    HtmlElementCollection secondPage;

    public Form1()
    {
        InitializeComponent();

    }

    private void button1_Click(object sender, EventArgs e)
    {
        // First Do login page if that comes up
        try
        {
            // Insert userName
            HtmlElementCollection firstPage = webBrowser1.Document.All;
            foreach (HtmlElement element in firstPage)
            {
                if (element.GetAttribute("className") == "logininput" && element.Name== "username" )
                {
                    element.SetAttribute("value","userName");
                }
            }

            // Insert password

            foreach (HtmlElement element in firstPage)
            {
                if (element.GetAttribute("className") == "logininput" && element.Name == "password")
                {
                    element.SetAttribute("value", "Password");
                }
            }
            // Submit
            webBrowser1.Document.GetElementById("loginsubmit").InvokeMember("click");

        }
        catch(Exception ex)
        {
            MessageBox.Show(ex.ToString());
        }
        try
        {

            System.Threading.Thread.Sleep(2000);
            //Search For Part
            var mfgPartNumber = "CRCW12061R00FKEA";
            webBrowser1.Document.GetElementById("txtsearch").SetAttribute("value", mfgPartNumber);
            webBrowser1.Document.GetElementById("btnsearch").InvokeMember("click");

            System.Threading.Thread.Sleep(50);
            //Get Part
            secondPage = webBrowser1.Document.All;
            foreach (HtmlElement element in secondPage)
            {
                if (element.GetAttribute("className") == "SE-Content-PartSearch-Grid-Row-Description")
                {
                    MessageBox.Show("got here");
                }
            }

        }
        catch(Exception ex)
        {
            MessageBox.Show(ex.ToString());
        }
    }

    private void button2_Click(object sender, EventArgs e)
    {
         firstPage = webBrowser1.Document.All;
        foreach (HtmlElement element in firstPage)
        {
            if (element.GetAttribute("className") == "SE-BannerLogoutLable")
            {
                element.InvokeMember("click");
            }
        }
    }
}