Question

I have this code that is supposed to load the attributes of an XML file to a string variable when the user clicks a button:

    public void Button1_Click(object sender, EventArgs e)
    {
        XDocument doc = XDocument.Load("C:/Structure.xml");
        Visit(doc.Root);


    }

    public static void Visit(XElement element)
    {

        string siteURL1 = element.Attribute("URL").Value;
        string siteTitle1 = element.Attribute("siteTitle").Value;
        string siteDescription1 = element.Attribute("siteDescription").Value;
        string siteTemplate = element.Attribute("siteTemplate").Value;
        string name = element.Attribute("type").Value;
        Execute(name, siteURL1, siteTitle1, siteDescription1, siteTemplate); 
}

But when I deploy the webpart, and click the button, I get the “NullreferenceException was unhandled by user code / Object reference not set to an instance of an object” errors. on:

  string siteURL1 = element.Attribute("URL").Value;" 

Any idea of what I may be doing wrong?

This is what the structure looks something like this:

<root>
  <level1 name="level1A"
          type="Private"
          template="3 
          siteTitle="Private"
          siteDescription="Private Site"  
          URL"private">
    <level2 name="level2A">
      <level3 name="level3A">
        <level4 name="level4A">
          <level5 name="level5A">
            <level6 name="level6A">
              <level7 name="level7A">
                <level8 name="level8A"></level8>
              </level7>
            </level6>
          </level5>
        </level4>
      </level3>
    </level2>
  </level1>
</root> 

Answer 1

One of two things I could see being wrong…

Either the object element is null

or

the attribute URL doesn’t exist for that element

Try something like…

var url = element.Attribute("URL");
string siteURL1;

if(url != null)
{
   siteURL1 = url.Value;
}