Word table extractor

WordTableExtractor.cs

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

//Usage:
// var tables = new WordTableExtractor().ExtractTables(@"path\to\my\file.docx");

public class WordTableExtractor
{
    public IEnumerable<IEnumerable<string[]>> ExtractTables(string filename)
    {
        return ExtractTables(ReadDocxFile(filename, "word/document.xml"));
    }

    public IEnumerable<IEnumerable<string[]>> ExtractTables(string filename, string entry)
    {
        return ExtractTables(ReadDocxFile(filename, entry));
    }

    private static IEnumerable<IEnumerable<string[]>> ExtractTables(XmlDocument doc)
    {
        var nsmgr = new XmlNamespaceManager(doc.NameTable);
        nsmgr.AddNamespace("w", "http://schemas.openxmlformats.org/wordprocessingml/2006/main");

        return SelectNodes(doc.DocumentElement, "//w:tbl", nsmgr)   //Find all tables
                .Select(t => SelectNodes(t, "w:tr", nsmgr)          //Find their rows
                .Select(r => SelectNodes(r, "w:tc", nsmgr)          //Find their cells
                .Select(c => c.InnerText.Trim()).ToArray()          //Get their textcontent
                ));
    }

    private static IEnumerable<XmlElement> SelectNodes(XmlElement element, string xpath, XmlNamespaceManager nsmgr)
    {
        return element.SelectNodes(xpath, nsmgr).Cast<XmlElement>();
    }

    private static XmlDocument ReadDocxFile(string path, string entry)
    {
        using (var s = File.OpenRead(path))
        {
            using (var z = new ZipArchive(s, ZipArchiveMode.Read))
            {
                var f = z.Entries.FirstOrDefault(e => e.FullName.Equals(entry, StringComparison.OrdinalIgnoreCase));
                if (f == null)
                    throw new FileNotFoundException(string.Format("Entry '{0}' was not found in '{1}'", entry, path));

                using (var sr = f.Open())
                {
                    var x = new XmlDocument();
                    x.Load(sr);
                    return x;
                }
            }
        }
    }
}