根据同级节点的值选择XML节点

Question

I have a VB.NET 2013 program that reads from/writes to an xml document and I'm trying to figure out how to access a specific node when I know the text of one of the node's siblings. I've seen other posts that are similar to what I'm trying to do, but my xml structure is slightly different and I'm not sure how to apply those solutions to my document.

Here's a sample of my xml structure:

<?xml version="1.0" encoding="utf-8"?>
<Books>
  <Book>
    <Title>Hansel and Gretel</Title>
    <Pages>221</Pages>
    <Price>3.5</Price>
    <Author>Grimm</Author>
  </Book>
  <Book>
    <Title>Green Eggs and Ham</Title>
    <Pages>145</Pages>
    <Price>5.25</Price>
    <Author>Dr. Seuss</Author>
  </Book>
</Books>

The examples I've seen in other posts have values in the node name <Title title="Green Eggs and Ham"> . As you can see, mine doesn't.

I can't figure out how to use XPath, XPathNavigator, etc for my xml document to find a price, for instance if I know the title.

I see a lot of examples that look like: /Books/Book[@Title="Green Eggs and Ham"] , and I tried using that with XPathNavigator.SelectSingleNode(), but I can't figure out the correct VB.Net/XPath syntax to use with my xml format.

UPDATE (Example answer) Since I'm using this in a VB.NET project, I needed to know how to use the examples that Bogdan and ThW gave. Using my sample XML I did this to get the number of pages for the title "Hansel and Gretel":

Dim xpathDoc As XPathDocument = New XPathDocument([path_to_xml)
Dim xmlNav as XPathNavigator = xpathDoc.CreateNavigator()
Dim pages as String

pages = xmlNav.SelectSingleNode("/Books/Book[Title='Hansel and Gretel']/Pages").Value

Which, of course, returns "221"

Answer 1

The @ in XPath ist a shortcut for attribute:: . It selects attributes nodes (or more specific nodes on the attributes axis).

Your Title node is an element node. It is a child of the Book element node. child is the default axis, so it is optional. Basically /Books/Book is short for /child::Books/child::Book .

The part in [] is a condition for the nodes. [@Title="Green Eggs and Ham"] filters the node for an attribute Title with the given value.

To look for the child element node Title remove the @ .

/Books/Book[Title="Green Eggs and Ham"]

Answer 2

//Book/Title[text()='Green Eggs and Ham']/../Price

text() searches in value. .. selects parent element

EDIT

Thanks ThW for explanation about . , removed from answer.