HtmlAgilityPack algorithm question - html-agility-pack

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"> </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