Question

I’m using HtmlAgilityPack to obtain some Html from a web site.

Here is the received Html:

<table class="table">
<tr>
    <td>
        <table class="innertable">...</table>
    </td>
</tr>
<tr>
    <td colspan="2"><strong>Contact</strong></td>
</tr>
<tr>
    <td colspan="2">John Doe</td>
</tr>
<tr>
    <td colspan="2">Jane Doe</td>
</tr>
<tr>
    <td colspan="2">&nbsp;</td>
</tr>
<tr>
    <td><strong>Units</strong></td>
    <td>32</td>
</tr>
<tr>
    <td><strong>Year</strong></td>
    <td>1998</td>
</tr>
</table>

---

The Context:

I’m using the following code to get the first :

var table = document.DocumentNode.SelectNodes("//table[@class='table']").FirstOrDefault();

I’m using the following code to get the inner table :

var innerTable = table.SelectNodes("//table[@class=innertable]").FirstOrDefault();

So far so good!

I need to get some information from the first table and some from the inner table.
Since I begin with the information from the first table I need to skip the first row (which holds the inner table) so I do the following:

var tableCells = table.SelectNodes("tr[position() > 1]/td");

Since I now have all the cells from the first table excluding the inner table, I start doing the following:

string contact1 = HttpUtility.HtmlDecode(tableCells[1].InnerHtml);
string contact2 = HttpUtility.HtmlDecode(tableCells[2].InnerHtml);

string units = HttpUtility.HtmlDecode(tableCells[5].InnerHtml);
string years = HttpUtility.HtmlDecode(tableCells[7].InnerHtml);

---

The problem:

I’m getting the values I want by hardcoding the index in tableCells[] not thinking the layout would move…unfortunately, it does move.

In some cases I do not have a “Jane Doe” row (as shown in the above Html), this means I may or may not have two contacts.

Because of this, I can’t hardcode the indexes since I might end up having the wrong data in the wrong variables.

So I need to change my approach…

Does anyone know how I could perfect my algorithm so that it can take into account the fact that I may have one or two contacts and perhaps not use hardcoded indexes?

Thanks in advance!

vlince

Answer 1

There is never one unique solution to this kind of problem. Here is an XPATH that seems to do some kind of it though:

        HtmlAgilityPack.HtmlDocument doc = new HtmlAgilityPack.HtmlDocument();
        doc.Load(yourHtmlFile);

        doc.Save(Console.Out);

        foreach (HtmlNode node in doc.DocumentNode.SelectNodes("//tr[td/strong/text() = 'Contact']/following-sibling::tr/td/text()[. != ' ']"))
        {
            Console.WriteLine(node.OuterHtml);
        }

will display this:

John Doe
Jane Doe
32
1998