title: C#/XML: 'System.Xml.XmlDocument' does not contain a definition for 'Descendants'
body: <p>I just received an error a while ago from this code:</p>
  
  <pre><code>private void ShowXMLDatatoRTB() {
  XmlDocument xmlDoc = new XmlDocument();
  xmlDoc.Load("XMLFile.xml");
  
  var persons = from person in xmlDoc.Descendants("Person")
          select new
              {
                  Name = person.Element("Name").Value,
                      City = person.Element("City").Value,
                  Age = person.Element("Age").Value,
              };
  
  richTextBox1.Text = "";
  foreach (var person in persons)
  {
      richTextBox1.Text = richTextBox1.Text + "Name: " + person.Name + "\n";
              richTextBox1.Text = richTextBox1.Text + "City: " + person.City + "\n";
              richTextBox1.Text = richTextBox1.Text + "Age: " + person.Age + "\n\n";
      }
  
  if (richTextBox1.Text == "")
              richTextBox1.Text = "No Results."; }
  </code></pre>
  
  <p>Am I missing something?</p>