vb.net - 我在单击按钮的代码部分收到 System.NullReferenceException

Question

我在单击按钮的代码部分收到 System.NullReferenceException。我有问题WebBrowser1.Document.GetElementById("Giriş Yap").InvokeMember("click")。同时我不是编码员，我在 web.xml 中找到了该代码。我想做自动 facebook 登录代码。

Public Class Form1

Private Sub Button1_Click(ByVal sender As System.Object, 
                          ByVal e As System.EventArgs) Handles Button1.Click
    WebBrowser1.Navigate("https://www.facebook.com/")
End Sub

Private Sub Button2_Click(ByVal sender As System.Object, 
                          ByVal e As System.EventArgs) Handles Button2.Click
    WebBrowser1.Document.GetElementById("email").SetAttribute("value", TextBox1.Text)
    WebBrowser1.Document.GetElementById("pass").SetAttribute("value", TextBox2.Text)

    WebBrowser1.Document.GetElementById("Giriş Yap").InvokeMember("click")
End Sub

End Class