How to get data from an XML File in C# using XMLDocument class?

Question

Good Evening All, and happy weekend!.

I have been trying all day to understand how to parse my simple XML file so I can understand it enough to write a personal project I want to work on.

I have been reading articles on this site and others but cannot get past where I am :(

My XML Document is ...

<XML>
  <User>
    <ID>123456789</ID>
    <Device>My PC</Device>
  </User>
  <History>
    <CreationTime>27 June 2013</CreationTime>
    <UpdatedTime>29 June 2013</UpdatedTime>
    <LastUsage>30 June 2013</LastUsage>
    <UsageCount>103</UsageCount>
  </History>
  <Configuration>
    <Name>Test Item</Name>
    <Details>READ ME</Details>
    <Enabled>true</Enabled>   
  </Configuration>
</XML>

I am trying to get the value in the details element (READ ME). Below is my code

// Start Logging Progress
Console.WriteLine("Test Application - XML Parsing and Creating");
Console.ReadKey();

// Load XML Document
XmlDocument MyDoc = new XmlDocument();  MyDoc.Load(@"E:\MyXML.XML");

// Select Node
XmlNode MyNode = MyDoc.SelectSingleNode("XML/Configuration/Details");

// Output Node Value
Console.WriteLine(String.Concat("Details: ", MyNode.Value));

// Pause
Console.ReadKey();

My console application is running and outputing "Target: " but not giving me the detail within the element.

Can somebody see why this is happening, and perhaps give me advice if I am completely off the wheel? I have no previous knowledge in reading XML files; hence where I am now :)

Thanks! Tom

Answer 1

With the your XPATH expression

// Select Node
XmlNode MyNode = MyDoc.SelectSingleNode("XML/Configuration/Details");

your are selection an element so the type of the MyNode will be XmlElement but the Value of an XmlElement is always null (see on MSDN ) so you need to use XmlElement.InnerText or XmlElement.InnerXml isntead.

So the changed your code to

// Output Node Value
Console.WriteLine(String.Concat("Details: ", MyNode.InnerText));

Or you can select the content of an element with using the XPATH text() function, in this case MyNode will be XmlText where you get its value with Value :

// Select Node
XmlNode MyNode = MyDoc.SelectSingleNode("XML/Configuration/Details/text()");

// Output Node Value
Console.WriteLine(String.Concat("Details: ", MyNode.Value));

As a sidenote if you are anyway learning XML manipulation in C# you should check out LINQ to XML which is another/newer way to working with XML in C#.

Answer 2

Just for interest, a little-known "simple" syntax is this:

XmlDocument myDoc = new XmlDocument();
myDoc.Load(@"D:\MyXML.XML");

string details = myDoc["XML"]["Configuration"]["Details"].InnerText;

Note that this (and the XPath approach) could go pop if your XML doesn't conform to the structure you're expecting, so you'd ideally put some validation in there as well.

Answer 3

U can use Xpath library for that (u must include "System.Xml.XPath"):

 XmlDocument document = new XmlDocument();
         document.Load("MyXml.xml");
         XPathNavigator navigator = document.CreateNavigator();

        foreach (XPathNavigator nav in navigator.Select("//Details"))
         {
             Console.WriteLine(nav.Value);

        }

the above code iterate over every node called (Details) extracting information and print it.

Answer 4

If you want to retrieve a particular value from an XML file

 XmlDocument _LocalInfo_Xml = new XmlDocument();
            _LocalInfo_Xml.Load(fileName);
            XmlElement _XmlElement;
            _XmlElement = _LocalInfo_Xml.GetElementsByTagName("UserId")[0] as XmlElement;
            string Value = _XmlElement.InnerText;

Value contains the text value