InnerText z textboxa w GeckoFx

Witam, jak pobrać wartości wpisane w textboxach loginu i hasła w GeckoFx?

private void button1_Click(object sender, EventArgs e)
        {
            var inputElements = geckoWebBrowser1.Document.GetElementsByTagName("input");
            foreach (GeckoHtmlElement i in inputElements)
            {
                if (i.GetAttribute("name").Equals("usernames"))
                {
                    i.InnerHtml = textBox1.Text;
                }
                if (i.GetAttribute("name").Equals("passwords"))
                {
                    i.Focus();
                    i.InnerHtml = textBox2.Text;
                }
            }

            var buttonElement = geckoWebBrowser1.Document.GetElementsByTagName("button");
            foreach (GeckoHtmlElement b in buttonElement)
            {
                if (b.GetAttribute("type").Equals("submit"))
                {
                    b.Click();
                }
            }
        }

Po InnerHtml nie pobiera danych z textboxów na stronę logowania