HTMLAgilityPack and XPath Target

我有以下HTML：

<table>
    <tr>
        <td><a href="#">Tournament Name</a>
            <br /> Tournament Address </td>
    </tr>
    <tr>
        <td><a>View Available Space and Book Online</a></td>
    </tr>
    <tr>
        <td>
            <em>Event Cost:</em> $$$
        </td>
        <td> Date and Time </td>
    </tr>
    <tr>
        <td>
            <p>
                <strong>
                    <img title="Boy's Teams can enter this tournament" />
                    <img  title="Girl's Teams can not enter this tournament" />
                    <img  title="Disabled Teams can not enter this tournament" />
                </strong>
            </p>
        </td>
        <td>
            TimeFrame
        </td>
    </tr>
     <tr>
       <td>
            <img src="image.gif" />
            <img src="image.gif" />
            <img src="image.gif" />
            <img src="image.gif" />
            <img src="image.gif" />
            <img src="image.gif" />
            <img src="image.gif" />
            <img src="image...." />
            <img src="image...." />
            <img src="image...." />
            <img src="image...." />
        </td>
    </tr>
</table>

（此表在页面上重复多次）。

我正在尝试提取锦标赛名称

我有以下C#代码：

namespace AcademyScraper
{
    public partial class Main : Form
    {
        public Main()
        {
            InitializeComponent();
        }

        private void saveBtn_Click(object sender, EventArgs e)
        {
            string url = "http://www.reddishvulcans.com/uk_tournament_database.asp";
            var Webget = new HtmlWeb();
            var doc = Webget.Load(url);
            var root = doc.DocumentNode;
            var nodes = root.Descendants();
            HtmlNodeCollection tableCollection = doc.DocumentNode.SelectNodes("//div[@class='infobox']/table");
            for (Int32 i = 0; i < tableCollection.Count(); i++)
            {
            HtmlNode tournamentName = tableCollection[i].SelectSingleNode("/tr[1]/td/a");
            MessageBox.Show(tournamentName.InnerText);
            // I get an exception here
            }
        }

    }
}

我遇到的问题是，无论我做什么，我似乎都无法瞄准包含锦标赛名称的标签。如果我执行MessageBox.Show(tableCollection[i].OuterHTML);，那么表内容将在消息框中呈现良好，不会出现任何问题。然而，每当我试图获得锦标赛名称时，我都会得到一个引用异常。基于HTML，我认为它应该是正确的。

 private void saveBtn_Click(object sender, EventArgs e)
    {
        string url = "http://www.reddishvulcans.com/uk_tournament_database.asp";
        var Webget = new HtmlWeb();
        var doc = Webget.Load(url);
        var aTags = doc.DocumentNode.SelectNodes("//div[@class='infobox']/table/tr/td[1]/a");
        foreach (var tag in aTags)
        {
            Console.WriteLine(tag.InnerText);
        }
        Console.ReadLine();
    }

//div[@class='infobox']/table/tr/td[br]/a

string url = "http://www.reddishvulcans.com/uk_tournament_database.asp";
var Webget = new HtmlWeb();
var doc = Webget.Load(url);
//print top 10 result just for the sake of demo
var result = doc.DocumentNode
                .SelectNodes("//div[@class='infobox']/table/tr/td[br]/a")
                .Take(10);
foreach (HtmlNode node in result)
{
    Console.WriteLine(node.InnerText);
}

The North West Junior Champions League 2016
PLAY AT CHELSEA - STAMFORD BRIDGE FOOTBALL TOURNAMENT 2016
PLAY AT FC BARCELONA -  CAMP NOU FOOTBALL TOUR 2016 - THE EUROPA CUP
Silverdale Soccersevens XIX
NORTH HALIFAX MINI SOCCER TOURNAMENT 2016
Halton & District JFL Mini Soccer Tournament
Colwyn Bay FC Junior Tournament
GMCJFC Pat Mangan Festival of Football 2016
Fred England Trophy
Fred England Trophy