c# Getting out of range when trying to parse XML into ListBox

Question

I'm new to programming but, I'm trying to load all entries of one single field in a XML file into a ListBox. This seems to properly load the XML file on executing the form but, I get an out of range exception with this code:

using System.Xml.Serialization;
using System.IO;
using System.Xml;
using System.Xml.Linq;

namespace TP1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();

            XmlDocument xmldocIntern = new XmlDocument();
            xmldocIntern.Load(@"InternList.xml");

            foreach (XmlNode node in xmldocIntern.DocumentElement)
            {
                string theTitle = node.Attributes[0].Value;

                lstBxListIntern.Items.Add(theTitle);
            }

        }

This is a sample of my XML file:

<?xml version="1.0"?>
<ArrayOfInternship xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <Internship>
    <Title>Marketing</Title>
    <Start>2019-03-08T00:00:00</Start>
    <End>2019-04-12T00:00:00</End>
    <Supervisor>John Smith</Supervisor>
    <Comments>Web site makeover.</Comments>
  </Internship>  
</ArrayOfInternship>

Answer 1

I wrote some basic example and I used your XML file.. You can examine that..

XML file

<?xml version="1.0"?>
<ArrayOfInternship xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <Internship>
    <Title>Marketing</Title>
    <Start>2019-03-08T00:00:00</Start>
    <End>2019-04-12T00:00:00</End>
    <Supervisor>John Smith</Supervisor>
    <Comments>Web site makeover.</Comments>
  </Internship>  
  <Internship>
    <Title>Marketing 2</Title>
    <Start>2019-03-08T00:00:00</Start>
    <End>2019-04-12T00:00:00</End>
    <Supervisor>John Smith</Supervisor>
    <Comments>Web site makeover.</Comments>
  </Internship> 
</ArrayOfInternship>

this is the model which one is you will use

public class InternshipModel
{
    public string Title { get; set; }
    public string Start { get; set; }
    public string End{ get; set; }
    public string Supervisor{ get; set; }
    public string Comments{ get; set; }
}

this part pars xml file and add to listbox

 // Loading from a file, you can also load from a stream
 var xml = XDocument.Load(@"InternList.xml");

 // Query the data and write out a subset of contacts
 var query = (from c in xml.Root.Descendants("Internship")
              select new InternshipModel
              {
                 Title = c.Element("Title").Value,
                 Start = c.Element("Start").Value,
                 End = c.Element("End").Value,
                 Supervisor = c.Element("Supervisor").Value,
                 Comments = c.Element("Comments").Value
              }).ToList();

 foreach (InternshipModel model in query)
 {
     listBox1.Items.Add("Title: " + model.Title +
                        "Start: " + model.Start +
                        "End: " + model.End +
                        "Supervisor: " + model.Supervisor +
                        "Comments: " + model.Comments);
 }

Answer 2

I think you may be having an issue with trying to get the value of the Title tag because you're trying to grab the first attribute of every XML element but the only element that has an attribute is ArrayOfInternship.

There are a couple of ways that you could extract all of the titles from all Internship elements in the array.

First would be looping and uses the XmlDocument class like what your code uses

XmlDocument doc = new XmlDocument();
doc.Load(@"InternList.xml");

// Loop over child nodes of <ArrayOfInternship>...
foreach (XmlNode node in doc.DocumentElement)
{
    // Loop over the child nodes of the <Internship> nodes
    foreach (XmlNode child in node.ChildNodes)
    {
        if (child.Name.Equals("Title", StringComparison.OrdinalIgnoreCase))
        {
            lstBxListIntern.Items.Add(child.InnerText);
        }
    }
}

The second solution that I came up with and personally like better because it's more succinct. You probably want to utilize the above solution since you are a beginner and it will most likely be easier for you to read. But here's the other solution using LINQ to XML.

XElement xml = XElement.Load(@"InternList.xml");

var titles = xml.Descendants("Title")
    .Select(x => x.Value)
    .ToList();

lstBxListIntern.Items.AddRange(titles);

Let me know if you need any clarification on what I mentioned and I'll be happy to clarify.

Answer 3

One possible solution

XmlDocument xmldocIntern = new XmlDocument();
xmldocIntern.Load(@"InternList.xml");

var oc = new ListBox.ObjectCollection(lstBxListIntern, xmldocIntern.DocumentElement.GetElementsByTagName("Title").Cast<XmlNode>().Select(node => node.InnerText).ToArray());