C#: using xpath to find matching node

Posted on 2014-04-29
Last Modified: 2016-02-18
I have the following method which loops through the <desc> node in an xml file to find if it matches the parameter "msg".
What I need to do is ,once found retrieve the <code> from the xml. How do I do that?

        static string getCode(string msg)
            string filename = @"C:\temp\errors.xml";
            string xmlCode="";

            XmlDocument doc = new XmlDocument();
            XmlNodeList nodes = doc.SelectNodes("/edt/ce/desc");

            foreach (XmlNode node in nodes)
                if (node.InnerText.Trim().Equals(msg))
                    xmlCode = "Found";  //should be the <code> associated to the matching <desc>
                    xmlCode = "Not found";


            msg = xmlCode;

            return msg;
This is errors.xml
<edt name="errors">
            <desc>Not here</desc>
            <desc>Invalid Input </desc>
Question by:badtz7229
  • 3
  • 2

Expert Comment

by:deepu chandran
ID: 40031281
Please try LINQ to SQL, Below code will work

IEnumerable<XElement> xmlDocuments = from x in XElement.Load(@"d:\deepu\sample.xml").Elements("ce")
                                             select x;

        var elements = from c in xmlDocuments
                       select c;

Open in new window

LVL 52

Assisted Solution

by:Carl Tawn
Carl Tawn earned 500 total points
ID: 40031410
You can achieve what you want in one step, rather than resorting to a loop:
XmlNode node = doc.SelectSingleNode("/edt/ce[desc='" + msg + "']/code");
if (node != null)
      // found the correct node

     string code = node.InnerText;

Open in new window


Author Comment

ID: 40031882
How do I trim <desc> before inserting he parameter? Bc sometimes there's a trailing spaces in the XML file and the match won't be found
How Do You Stack Up Against Your Peers?

With today’s modern enterprise so dependent on digital infrastructures, the impact of major incidents has increased dramatically. Grab the report now to gain insight into how your organization ranks against your peers and learn best-in-class strategies to resolve incidents.

LVL 52

Accepted Solution

Carl Tawn earned 500 total points
ID: 40031900
The normalize-space XPath function will trim whitespace from the start and end of the string:
XmlNode node = doc.SelectSingleNode("/edt/ce[normalize-space(desc)='" + msg + "']/code");

Open in new window


Author Closing Comment

ID: 40032003
thank you, this worked successfully.

Author Comment

ID: 40032396
how do i use your solution in the event that the msg parameter contains an apostrophe?
(i.e. - Can't create Server object). This string exists in the xml

Featured Post

Free Tool: Subnet Calculator

The subnet calculator helps you design networks by taking an IP address and network mask and returning information such as network, broadcast address, and host range.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

This article describes a simple method to resize a control at runtime.  It includes ready-to-use source code and a complete sample demonstration application.  We'll also talk about C# Extension Methods. Introduction In one of my applications…
Calculating holidays and working days is a function that is often needed yet it is not one found within the Framework. This article presents one approach to building a working-day calculator for use in .NET.
The Email Laundry PDF encryption service allows companies to send confidential encrypted  emails to anybody. The PDF document can also contain attachments that are embedded in the encrypted PDF. The password is randomly generated by The Email Laundr…

713 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question