Select XML Nodes by Parent attribute

[AdrianGawrys]

Hi Guys,

I have an xml similar to this one:

<?xml version="1.0" encoding="UTF-8"?>
<SystemUpdate ForceUpdate="false" >
  <A ForceUpdate="false">
    <Book name="Black" />
    <Book name="BlackRed" />
    <Book name="Red" />
    <Book name="Green" ForceUpdate="true"/>
  </A>
  <B ForceUpdate="true">
     <Book name="Old" />
     <Book name="New"/>
  </B>
</CapUpdate>

Can someone help me out and explain whats the simplest way of selecting nodes that have it's own or parent node's attribute: ForceUpdate set to true.

Ie.: SystemUpdate's ForceUpdate is set to true = that will select all Book nodes,
A node's ForceUpdate set to true = this will select Black,BlackRed, Red and Green Book nodes.
B node's ForceUpdate set to true = this will select "Old" and "New" Book nodes.
So in the quoted xml example selected nodes would be: Green,Old and New.

Hope I explained it correctly.
I was trying to find something that works similar but had no luck.

Thanks in advance.
Adrian

[Plater]

Well in the javascript world, you can use an XPATH statement to do that.
I think the XML objects in .NET have similar abilities?

[vekipeki]

You can use XmlReader, to get values of your attributes:

XmlReader reader = new XmlTextReader(inputStream);
reader.ReadToFollowing("A");
string attributeValue = reader.GetAttribute("ForceUpdate");

XmlReader.GetAt tribute will return 'true' or 'false' (or null if that attribute does not exist for the current element).

[AdrianGawrys]

Thanks for your responses guys.

@vekipeki - I should have mentioned that I am able to select a node and test for attribute's value, but I am more interested in some sort of xpath statement that will get select all nodes that have a parent node with attribute ForceUpdate set to 'true' and store them into XmlNodeList variable.
@plater - would you be able to sketch statement in Javascript that does that?

Thanks,

Adrian

[Plater]

Well I can never keep my head wrapped around XPath to be sure, but I really liked the examples found here:

http://www.zvon.org/xxl/XPathTutorial/General/examples.html

Example #6 looks most like what you want for selecting by an attribute.
I think you can combine it with /*

I came up with:
//*[@ForceUpdate="t rue"]/*

Which i *think* means "select all nodes that are children of any nodes with attribute ForceUpdate = true"

[AdrianGawrys]

@Plater you have no idea how grateful I am for the link to examples you've sent.
I was never too good with XPath but that helped me to understand it.
Currently I've achieved what I wanted with two XPath queries - one for all book nodes that have 'ForceUpdate' attribute set to true and another query that selects all Book nodes whose Parent nodes have ForceUpdate set to true.

What I need to do now is just to combine them into one.

I will post my XPath query shortly.

Thanks again for your help!

Adrian