How can I transform XML into a List<string> or String[]?

Question

How can I transform the following XML into a List<string> or String[]:

<Ids>
  <id>1</id>
  <id>2</id>
</Ids>

Answer 1

It sounds like you're more after just parsing rather than full XML serialization/deserialization. If you can use LINQ to XML, this is pretty easy:

using System;
using System.Linq;
using System.Xml.Linq;

public class Test
{
    static void Main()
    {
        string xml = "<Ids><id>1</id><id>2</id></Ids>";

        XDocument doc = XDocument.Parse(xml);

        var list = doc.Root.Elements("id")
                           .Select(element => element.Value)
                           .ToList();

        foreach (string value in list)
        {
            Console.WriteLine(value);
        }
    }
}

In fact the call to Elements could omit the argument as there are only id elements, but I thought I'd demonstrate how to specify which elements you want.

Likewise I'd normally not bother calling ToList unless I really needed a List<string> - without it, the result is IEnumerable<string> which is fine if you're just iterating over it once. To create an array instead, use ToArray.

Answer 2

This sample will work with the .NET framework 3.5:

    System.Xml.Linq.XElement element = System.Xml.Linq.XElement.Parse("<Ids>  <id>1</id>  <id>2</id></Ids>");
    System.Collections.Generic.List<string> ids = new System.Collections.Generic.List<string>();
    foreach (System.Xml.Linq.XElement childElement in element.Descendants("id"))
    {
        ids.Add(childElement.Value);
    }

Answer 3

Here is a way using XmlDocument :

// A string containing the XML data
string xml = "<Ids><id>1</id><id>2</id></Ids>";
// The list you want to fill
ArrayList list = new ArrayList();

XmlDocument doc = new XmlDocument();
// Loading from a XML string (use Load() for file)
doc.LoadXml(xml); 
// Selecting node using XPath syntax
XmlNodeList idNodes = doc.SelectNodes("Ids/id");
// Filling the list
foreach (XmlNode node in idNodes)
    list.Add(node.InnerText);

Answer 4

You can use Properties class.

Properties prop = new Properties();
prop.loadFromXML(stream);
Set set = prop.keySet();

You can than access Strings from set for each key. Key is element name of xml.

Answer 5

Here's a way to get typed array from xml by using DataSets. (in this example array of doubles)

DataSet dataSet = new DataSet()
DoubleArray doubles = new DoubleArray(dataSet,0);

dataSet.ReadXml("my.xml");
double a = doubles[0];



public class DoubleArray
{
  DataSet dataSet;
  int tableIndex;
  public DoubleArray(DataSet dataSet,int tableIndex)
  {
    this.dataSet=dataSet;
    this.tableIndex=tableIndex;
  }

  public double this[int index]
  {
    get
    { 
      object ret = dataSet.Tables[tableIndex].Rows[index];
      if(ret is double?) 
        return (ret as double?).Value;
      else
        return double.Parse(ret as string);
    }
    set
    {
      object out = dataSet.Tables[tableIndex].Rows[index];
      if(out is double?)
        dataSet.Tables[tableIndex].Rows[index] = (double?)value;
      else
        dataSet.Tables[tableIndex].Rows[index] = value.ToString();
    }
  }
}

Of course parsing doubles and converting them back to strings all the time might be considered as blasphemy by some programmers... Even for me it was hard not to think about such waste of resources... but I guess sometimes it's better to just turn another away.. don't stress it :)