[c#] Reading specific XML elements from XML file

This is how I would do it (the code below has been tested, full source provided below), begin by creating a class with common properties

    class Word
    {
        public string Base { get; set; }
        public string Category { get; set; }
        public string Id { get; set; }
    }

load using XDocument with INPUT_DATA for demonstration purposes and find element name with lexicon . . .

    XDocument doc = XDocument.Parse(INPUT_DATA);
    XElement lex = doc.Element("lexicon");

make sure there is a value and use linq to extract the word elements from it . . .

    Word[] catWords = null;
    if (lex != null)
    {
        IEnumerable<XElement> words = lex.Elements("word");
        catWords = (from itm in words
                    where itm.Element("category") != null
                        && itm.Element("category").Value == "verb"
                        && itm.Element("id") != null
                        && itm.Element("base") != null
                    select new Word() 
                    {
                        Base = itm.Element("base").Value,
                        Category = itm.Element("category").Value,
                        Id = itm.Element("id").Value,
                    }).ToArray<Word>();
    }

The where statement checks if the category element exists and that the category value is not null and then check it again that it is a verb. Then check that the other nodes also exists . . .

The linq query will return an IEnumerable< Typename > object, so we can call ToArray< Typename >() to cast the entire collection into the type we want.

Then print it to get . . .

[Found]
 Id: E0006429
 Base: abandon
 Category: verb

[Found]
 Id: E0006524
 Base: abolish
 Category: verb

Full Source:

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

namespace test
{
    class Program
    {

        class Word
        {
            public string Base { get; set; }
            public string Category { get; set; }
            public string Id { get; set; }
        }

        static void Main(string[] args)
        {
            XDocument doc = XDocument.Parse(INPUT_DATA);
            XElement lex = doc.Element("lexicon");
            Word[] catWords = null;
            if (lex != null)
            {
                IEnumerable<XElement> words = lex.Elements("word");
                catWords = (from itm in words
                            where itm.Element("category") != null
                                && itm.Element("category").Value == "verb"
                                && itm.Element("id") != null
                                && itm.Element("base") != null
                            select new Word() 
                            {
                                Base = itm.Element("base").Value,
                                Category = itm.Element("category").Value,
                                Id = itm.Element("id").Value,
                            }).ToArray<Word>();
            }

            //print it
            if (catWords != null)
            {
                Console.WriteLine("Words with <category> and value verb:\n");
                foreach (Word itm in catWords)
                    Console.WriteLine("[Found]\n Id: {0}\n Base: {1}\n Category: {2}\n", 
                        itm.Id, itm.Base, itm.Category);
            }
        }

        const string INPUT_DATA =
        @"<?xml version=""1.0""?>
        <lexicon>
        <word>
          <base>a</base>
          <category>determiner</category>
          <id>E0006419</id>
        </word>
        <word>
          <base>abandon</base>
          <category>verb</category>
          <id>E0006429</id>
          <ditransitive/>
          <transitive/>
        </word>
        <word>
          <base>abbey</base>
          <category>noun</category>
          <id>E0203496</id>
        </word>
        <word>
          <base>ability</base>
          <category>noun</category>
          <id>E0006490</id>
        </word>
        <word>
          <base>able</base>
          <category>adjective</category>
          <id>E0006510</id>
          <predicative/>
          <qualitative/>
        </word>
        <word>
          <base>abnormal</base>
          <category>adjective</category>
          <id>E0006517</id>
          <predicative/>
          <qualitative/>
        </word>
        <word>
          <base>abolish</base>
          <category>verb</category>
          <id>E0006524</id>
          <transitive/>
        </word>
        </lexicon>";

    }
}