XML C# Fast Way To Find Node

Question

Hi I am kind of new to XML and .NET. I was wondering how I can parse the following file. I want to be able to get the XmlNode based on an ID I will provide. Example:

<Data>
<Question id="1">
<Answer>ddd</Answer>
</Question>
</Data>

I want to somehow do this:

XmlDocument myDoc = new XmlDocument();
XmlElement myElem = myDoc.GetElementById("1");
Response.Write("Answer: "+myElem.ChildNodes[0].InnerXML);

This should give me the output of: "Answer: ddd".

Any help is greatly appricated, thank you.

Also I would prefer not to use LINQ, as I would like to master the XML component of .NET first.

Answer 1

The XML component of .Net was a piece of crap. Please don't subject yourself to it and just go LINQ to XML. By all considerations it's much easier to work with and runs faster.

Answer 2

pseudo code: myDoc.selectSingleNode("//Question[@id=whatever]") (just top off my head)

Answer 3

Eyeballing it with no compilation:

XmlNode node = myDoc.SelectSingleNode("Data/Question[@id='1']/Answer"); Response.Write("Answer: " + node.InnerText);

Of course changing the 1 to be a parameter would be ideal if you want something variable.

Answer 4

Prior to LINQ, I would have used SelectSingleNode with an XPath query. In the example above, the XPath would be something like "//Question[@id=1]/Answer". Now, I'd use LINQ because, as I understand it at least, you save overhead by not having to work with an XmlDocument object. By using an XElement and using a LINQ to XML extension method to query it for the node you want, you could do the whole thing in one or two lines of code and it will perform as good or better.

Here's an example one liner in LINQ using your xml snippet that doesn't even require instantiating an object to work with the xml:

string xml = "<Data><Question id=\"1\"><Answer>ddd</Answer></Question></Data>";
string answer = XElement.Parse(xml).Descendants("Question").
    Where(node => node.Attribute("id").Value == "1").
    Descendants("Answer").ElementAt(0).Value;

Answer 5

I think those pointing you at Linq and away from the XML components are correct. You may want to learn or use XPath for non .Net compatibility and Linq allows you to do that if you want. The XML components are not fun to work with.