Question

I am trying to parse an XML response from a website in C#. The response comes in a format similar to the following:

<Company>
    <Owner>Bob</Owner>
    <Contact>
        <address> -1 Infinite Loop </address>
        <phone>
            <LandLine>[phone]</LandLine>
            <Fax> [phone] </Fax>
        </phone>
        <email> [e-mail] </email>
    </Contact>
</Company>

The only information I want is the LandLine and Fax numbers. However my current approach seems really really poor quality. Essentially it is a bunch of nested while loops and checks to the Element name then reading the Content when I found the right Element. I am using something like the listing below:

XmlReader xml = XmlReader.Create(websiteResultStream, xmlSettings);

while(xml.Read()){
    if(xml.NodeType == XmlNodeType.Element){
        if(xml.Name.ToString() == "Phone"){
            while(xml.Read()) {
                if(xml.NodeType == XmlNodeType.Element) {
                     if(xml.Name.ToString() == "LandLine"){
                          xml.MoveToContent();
                          xml.ReadContentAsString();
                     }
                     if(xml.Name.ToString() == "Fax"){
                          xml.MoveToContent();
                          xml.ReadContentAsString();
                     }
                }
            }
        }
    }
}

I am newer to XML/C#, but the above method just screams bad code! I want to ensure that if the structure changes (i.e. there are addition phone number types like “mobile”) that the code is robust (hence the additional while loops)

Note: the above C# code is not exact, and lacks some checks etc, but it demonstrates my current abysmal disgusting approach

What is the best/cleanest way to simply extract the content from those two Elements if they are present?

Answer 1

The most light-weight approach for read-only access to specific nodes in an XML document is by using an XPathDocument together with an XPath expression:

XPathDocument xdoc = new XPathDocument(@"C:\sample\document.xml");
XPathNavigator node = xdoc.CreateNavigator()
    .SelectSingleNode("/Company/Contact/phone/LandLine");
if (node != null)
{
    string landline = node.Value;
}