Best way to read, modify, and write XML

Question

My plan is to read in an XML document using my C# program, search for particular entries which I\'d like to change, and then write out the modified document. However, I\'ve bec

Answer 1

Here's a tool I wrote to modify an IAR EWARM project (ewp) file, adding a linker define to the project. From the command line, you run it with 2 arguments, the input and output file names (*.ewp).

    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;
    using System.Xml;

    namespace ewp_tool
    {
        class Program
        {
            static void Main(string[] args)
            {
                XmlDocument doc = new XmlDocument();
                doc.Load(args[0]);

                XmlNodeList list = doc.SelectNodes("/project/configuration[name='Debug']/settings[name='ILINK']/data/option[name='IlinkConfigDefines']/state");
                foreach(XmlElement x in list) {
                    x.InnerText = "MAIN_APP=1";
                }

                using (XmlTextWriter xtw = new XmlTextWriter(args[1], Encoding.UTF8))
                {
                    //xtw.Formatting = Formatting.Indented; // leave this out, it breaks EWP!
                    doc.WriteContentTo(xtw);
                }
            }
        }
    }

The structure of the XML looks like this

    <U+FEFF><?xml version="1.0" encoding="iso-8859-1"?>
    <project>
      <fileVersion>2</fileVersion>
      <configuration>
        <name>Debug</name>
        <toolchain>
          <name>ARM</name>
        </toolchain>
        <debug>1</debug>

         ...

        <settings>
          <name>ILINK</name>
          <archiveVersion>0</archiveVersion>
          <data>

            ...

            <option>
              <name>IlinkConfigDefines</name>
              <state>MAIN_APP=0</state>
            </option>

Answer 2

Are the documents you are processing relatively small? If so, you could load them into memory using an XmlDocument object, modify it, and write the changes back out.

XmlDocument doc = new XmlDocument();
doc.Load("path_to_input_file");
// Make changes to the document.
using(XmlTextWriter xtw = new XmlTextWriter("path_to_output_file", Encoding.UTF8)) {
  xtw.Formatting = Formatting.Indented; // optional, if you want it to look nice
  doc.WriteContentTo(xtw);
}

Depending on the structure of the input XML, this could make your parsing code a bit simpler.