سوال: خطا در هنگام خواندن RSS سایت خبری

class RssItem
{
public string title;
public string link;
public string desciption;
public override string ToString()
{
retu title;
}
}
//------------------------------------------------------------
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
WebRequest wr = WebRequest.Create("http://www.cnn.com/rrs.php");//url to read rss site
Stream stream = wr.GetResponse().GetResponseStream();
XmlDocument rss = new XmlDocument();
rss.Load(stream);
XmlNodeList items = rss.SelectNodes("rss/channel/item");
foreach (XmlNode item in items )
{
RssItem rssItem = new RssItem();
rssItem.title = item.SelectSingleNode("title").InnerText;
rssItem.desciption = item.SelectSingleNode("description").InnerText;
rssItem.link = item.SelectSingleNode("link").InnerText;
listBox1.Items.Add(rssItem);
}
}