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Help with XPath select

Hello EE,

In my vb.net code, I do this to retrieves nodes :

Dim nodesTC As HtmlNodeCollection = docTC.DocumentNode.SelectNodes("//td[@class='myproduct']")

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now lets say there are 2 td class 'myProduct' ..

both <td> will have all the same nodes because they are repeted for every product right so far...

if I do :

For Each nodeTC As HtmlNode In nodesTC
MesssageBox.Show(nodeTC.SelectSingleNode("//span[@itemprop='price']").InnerText.Trim())
Next

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well because there are 2 same node in the Htmldocument (because of the 2 products with nodes name repeated) I will always get the same price duplicated because Im pretty sure my code passes on the same twice.. I need a way to remove or skip every time i go to next product... or to create a list of(integer) and I would go at item.index + 1 you know ?

... can you help me ? I hope my question is clear..

Thanks

zc2

"//span[@itemprop='price']" selects always the same node, because it always searches from the document's root. Remove the '//' to make it start searching from the "nodeTC" element:
"span[@itemprop='price']"

kaufmed

Can you provide a sample of the XML (doesn't need to be production data--just the structure is relevant)?

kaufmed

@zc2

because it always searches from the document's root.

That is not accurate. "//" searches relative to node it is executed against. This may or may not be the document root.

Philippe Renaud

ASKER

ok let me Tab correctly the html its all messed up. brb

kaufmed

If it's well-formed (as in XML-well-formed), then you can select File->New, and then select "XML File". Paste the HTML into the new file, then do a Ctrl+E+D combination to format the document.

zc2

That is not accurate. "//" searches relative to node it is executed against. This may or may not be the document root.

I'm sorry, but this is not true. "//" always searches from the root.
".//" searches from the current node.

Philippe Renaud

ASKER

have a look lets say I want the value of offerCount

there are: 3416 and also 33
XMLFile1.xml

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zc2

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kaufmed

@zc2

I'm sorry, but this is not true. "//" always searches from the root.

If you run "//" against a child node, then it certainly does function the way I mentioned. See for yourself:

Xml

<root>
  <child1>
    <data>This is what I'm after</data>
  </child1>
  <data>This is not what I'm after</data>
</root>

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Code

Imports System.Xml

Module Module1

    Sub Main()
        Dim xdoc As New XmlDocument

        xdoc.Load("xmlfile1.xml")

        For Each node As XmlNode In xdoc.SelectNodes("//child1")
            Dim targetChild As XmlNode = node.SelectSingleNode("//data") 

            ' By your logic, both "This is what I'm after" AND 
            ' "This is not what I'm after" should display. Only the first displays.
            Console.WriteLine(targetChild.InnerText)
        Next
    End Sub

End Module

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You seem to be going by the W3C spec. So to fit that, you can think of the currently selected node as the document root.

**Note: When I say "current" node, I am not talking about the node so far as XPath is concerned; rather I am talking about the HtmlNode/XmlNode in VB that you have selected. I can see that wasn't quite clear in my previous comment. As the original code was written, the "//" would not search from the actual document's root. So far as the spec is concerned, yes "//" searches from the document root. When it comes to using it in .NET, however, each time you select something into an XmlNode object, that node object effectively becomes its own document.

kaufmed

@PhilippeRenaud

Are you using Html Agility Pack?

Philippe Renaud

ASKER

Yes kaufmed, i use the pack

zc2

You seem to be going by the W3C spec. So to fit that, you can think of the currently selected node as the document root.

Ok, probably you're right. I don't works with .net, and when I work with MSXML from VBscript, I always execute .setProperty "SelectionLanguage", "XPath" before I do any selection.

kaufmed

OK, are you able to correlate zc2's example to fit your scenario? It should be along the lines of what you are trying to achieve.

Philippe Renaud

ASKER

thanks

Philippe Renaud

ASKER

can u guys help me with that one ?

https://www.experts-exchange.com/questions/28054658/Help-with-DataGridView-data.html