HTML Agility Pack

I want to parse the html table using html agility pack. I want to extract only some predefined column data from the table.

But I am new to parsing and html agility pack and I have tried but I don't know how to use the html agility pack for my need.

If anybody knows then give me example if possible

EDIT :

Is it possible to parse html table like if we want to extract the decided column names' data only ? Like there are 4 columns name,address,phno and I want to extract only name and address data.

There is an example of that in the discussion forums here. Scroll down a bit to see the table answer. I do wish they would provide better samples that were easier to find.

EDIT: To extract data from specific columns you would have to first find the <th> tags that correspond to the columns you want and remember their indexes. You would then need to find the <td> tags for the same indexes. Assuming you know the indexes of the columns you could do something like this:

HtmlDocument doc = new HtmlDocument();
doc.LoadHtml("http://somewhere.com");
HtmlNode table = doc.DocumentNode.SelectSingleNode("//table");
foreach (var row in table.SelectNodes("//tr"))
{
    HtmlNode addressNode = row.SelectSingleNode("td[2]");
    //do something with address here
    HtmlNode phoneNode = row.SelectSingleNode("td[5]");
    // do something with phone here
}

Edit2: If you don't know the indexes of the columns you could do the whole thing like this. I have not tested this.

HtmlDocument doc = new HtmlDocument();
doc.LoadHtml("http://somewhere.com");
var tables = doc.DocumentNode.SelectNodes("//table");

foreach(var table in tables)
{
    int addressIndex = -1;
    int phoneIndex = -1;
    var headers = table.SelectNodes("//th");
    for (int headerIndex = 0; headerIndex < headers.Count(); headerIndex++)
    {
        if (headers[headerIndex].InnerText == "address")
        {
            addressIndex = headerIndex;
        }
        else if (headers[headerIndex].InnerText == "phone")
        {
            phoneIndex = headerIndex;
        }
    }

    if (addressIndex != -1 && phoneIndex != -1)
    {
        foreach (var row in table.SelectNodes("//tr"))
        {
            HtmlNode addressNode = row.SelectSingleNode("td[addressIndex]");
            //do something with address here
            HtmlNode phoneNode = row.SelectSingleNode("td[phoneIndex]");
            // do something with phone here
        }
    }
}