C# .NET ช่วยได้ครับมีปัญหา StreamReader มาแล้วทำต่อไม่ได้ครับ

        private void button1_Click(object sender, EventArgs e)
        {
            string url = urlTextBox.Text;
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            StreamReader sr = new StreamReader(response.GetResponseStream());
            richTextBox1.Text = sr.ReadToEnd();
            webBrowser1.DocumentText = richTextBox1.Text;
            HtmlElement htmlElement = webBrowser1.Document.GetElementById("name");
            string data = htmlElement.InnerText;
            label1.Text = data;
            sr.Close();
        }