XMLReader - How to read this element/node pattern

Question

This is some XML I need to be able to read. I need to get the QualitySetting values for each Feature assigned to some variables:

   <?xml version="1.0" encoding="UTF-8" ?>
   <GraphicsConfig>
      <FX>
       <Off>
           <LocalisationName>$QUALITY_OFF;</LocalisationName>
        <Item>
            <Feature>LightCones</Feature>
            <QualitySetting>0</QualitySetting>
        </Item>
        <Item>
            <Feature>LensFlares</Feature>
            <QualitySetting>0</QualitySetting>
        </Item>
        <Item>
            <Feature>Debris</Feature>
            <QualitySetting>0</QualitySetting>
        </Item>
        <Item>
            <Feature>ParticleEffects</Feature>
            <QualitySetting>0</QualitySetting>
        </Item>
        <Item>
            <Feature>Trails</Feature>
            <QualitySetting>0</QualitySetting>
        </Item>
        <Item>
            <Feature>Beams</Feature>
            <QualitySetting>0</QualitySetting>
        </Item>
        <Item>
            <Feature>Fog</Feature>
            <QualitySetting>0</QualitySetting>
        </Item>
    </Off>
   </FX>
 </GraphicsConfig>

I am using XMLReader and I usually use something like:

Dim guiSettings = XElement.Load(_localAppDataFilePath & "\Frontier Developments\Elite Dangerous\Options\Graphics\GraphicsConfigurationOverride.xml")
            target = guiSettings.Element("GUIColour").Elements("Default").[Single]()
            r = target.Element("MatrixRed").Value

Open to doing this other ways, and if there is no easy way to do this, I am perfectly happy to just locate the <Feature> element with the appropriate name and then simply just read the very next node, but thought I'd ask as I always want to improve my XML editing knowledge.

Answer 1

The code below uses a combination of XmlReader and XML Linq. I've posted this solution a lot of times. My preference in this case is not to use XmlReader instead use XML Linq to put results into a dictionary and posted that code as well. For huge XML files it is always best to use XmlReader to avoid out of memory error.

I posted solution in both c# and vb.net

---

Imports System.Xml
Imports System.Xml.Linq
Module Module1

    Const FILENAME As String = "c:\temp\test.xml"
    Sub Main()
        Dim reader As XmlReader = XmlReader.Create(FILENAME)
        Dim items As List(Of Item) = New List(Of Item)()
        While (Not reader.EOF)

            If reader.Name <> "item" Then
                reader.ReadToFollowing("Item")
            End If

            If Not reader.EOF Then

                Dim xItem As XElement = XElement.ReadFrom(reader)
                Dim item As Item = New Item()
                item.feature = xItem.Element("Feature")
                item.setting = xItem.Element("QualitySetting")

                items.Add(item)
            End If
        End While

        'using a dictionary 
        Dim doc As XDocument = XDocument.Load(FILENAME)
        Dim dict As Dictionary(Of String, String) = doc.Descendants("Item") _
            .GroupBy(Function(x) x.Element("Feature").ToString(), Function(y) y.Element("QualitySetting").ToString()) _
            .ToDictionary(Function(x) x.Key, Function(y) y.FirstOrDefault())

    End Sub

End Module
Public Class Item

    Public feature As String
    Public setting As String
End Class

---

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

namespace ConsoleApplication1
{
    class Program
    {
        const string FILENAME = @"c:\temp\test.xml";
        static void Main(string[] args)
        {
            XmlReader reader = XmlReader.Create(FILENAME);
            List<Item> items = new List<Item>();
            while (!reader.EOF)
            {
                if(reader.Name != "item")
                {
                    reader.ReadToFollowing("Item");
                }
                if (!reader.EOF)
                {
                    XElement xItem = (XElement)XElement.ReadFrom(reader);
                    Item item = new Item() {
                        feature = (string)xItem.Element("Feature"),
                        setting = (string)xItem.Element("QualitySetting")
                    };

                    items.Add(item);
                }
            }

            //using a dictionary 
            XDocument doc = XDocument.Load(FILENAME);
            Dictionary<string, string> dict = doc.Descendants("Item")
                .GroupBy(x => (string)x.Element("Feature"), y => (string)y.Element("QualitySetting"))
                .ToDictionary(x => x.Key, y => y.FirstOrDefault());
        }
    }
    public class Item
    {
        public string feature { get; set; }
        public string setting { get; set; }
    }
}