My XML is like:
<root>
<section name="blah">
<item name="asdf">2222</item>
</section>
</root>
I will have multiple 'sections' in the XML, I want to fetch a particular section.
In this case, I need to get items that are in the section named "blah".
The xpath is then:
/root/section[#name='blah']/item
for example, in XmlDocument:
foreach(XmlElement item in doc.SelectNodes("/root/section[#name='blah']/item"))
{
Console.WriteLine(item.GetAttribute("name"));
Console.WriteLine(item.InnerText);
}
Edit re comments: if you just want the sections, then use:
/root/section[#name='blah']
but then you'll need to iterate the data manually (since you can theoretically have multiple sections named "blah", each of which can have multiple items).
Related
The relevant chunk of my xml is this:
[... lots of xml up here, including ancestor elements...]
<category id="MyCatID" ... >
<option ... >
<property id="MyPropID">The magic value I need</property>
[... lots of xml down here...]
My objective: Find the value of a <property> with id of MyPropID whose parent is <option> and whose grandparent (through <option>) is <category> containing the id of MyCatID.
Here is my attempted xpath:
//property[#id='MyPropID']/ancestor::category[#id='MyCatID']
In my .NET 4.7.2 that xpath query brings back all the xml inside the <category> element, which misses the mark. My hoped-for result is that it would bring back the value The magic value I need.
How is it done?
Why not reverse it, get the category with the ID you want and then navigate to the property with the ID you want? I'm not really sure how your XML looks, here's my pseudo attempt...
//category[#id='MyCatID']/option/property[#id='MyPropID']
And if for some reason you would really want to do it bottom-up way:
//property[#id='MyPropID']/../../../property[#id='MyPropID']
or
//property[#id='MyPropID']/ancestor::node()[3]/property[#id='MyPropID']
I want to modify the Node my XML File look like this.
<Tasks>
<Task>
<Title>Title of the Task</Title>
<Description>Description of the Task</Description>
<Done>false</Done>
</Task>
<Task>
<Title>Title of anotherTask</Title>
<Description>Description of anotherTask</Description>
<Done>true</Done>
</Task>
</Tasks>
I could adress the Node like this:
xmlDoc.SelectSingleNode("/Tasks/Task/Description").InnerText = "My Description";
However I have mulitple Tasks. How do I indicate which is which? I want to change the State of the Task "Done" from false to true.
You could iterate through each resulting node from something like this:
foreach( XmlNode xn in xmlDoc.SelectNodes("//Tasks"))
{
// Do something
}
Doing what you need to do on each node. More info on SelectNodes here: https://msdn.microsoft.com/en-us/library/system.xml.xmlnode.selectnodes%28v=vs.110%29.aspx
If you have control over the design of the XML, perhaps you should consider adding an ID to your task. An ID will allow you to make changes to an specific Task node instead of iterating through them or looking up by Task.Title.
You may also look at these articles:
https://msdn.microsoft.com/en-us/library/bb943906.aspx
How can I iterate though each child node in an XML file?
Having said all this, I feel your question is missing some more information on what is the criteria on when to do that something correctly. Could you expand some more? You will get better answers that way.
I've chosen the title here as my problem is I need to get the Item nodes mentioned in the example.
I have the following XML and am having problems using LINQ to query it, I've been able to parse XML before - however I've been stuck on this for hours and hope someone can help.
Here is my XML data below (example data):
<a:entry
xmlns:a="http://www.w3.org/2005/Atom">
<a:id>98765</a:id>
<info>Data Catalogue</info>
<data>
<items>
<item>
<id>123456</id>
<value>Item One</value>
</item>
<item>
<id>654321</id>
<value>Item Two</value>
</item>
</items>
</data>
<items>
<item>
<id>123456</id>
<value>Item One</value>
</item>
<item>
<id>654321</id>
<value>Item Two</value>
</item>
</items>
<a:author>
<a:name>Catalogue</a:name>
</a:author>
</a:entry>
I want to be able to extract the ID from the Item XML tag under Items, however there is an Items Tag with Item entries under data I DO NOT want these nodes at all - I want root/items/id/id if this were expressed as path. I've tried everything I know with LINQ so if someone could help, things to note although this is sample data it is based on the system - the format cannot be changed so that is not an acceptable solution.
I can't seem to determine where I'm going wrong - every LINQ expression I try returns nothing, I think the namespace is an issue and have tried to integrate this but I'm going in circles.
Solution must work in Silverlight and C#
I have tried the following:
IEnumerable<XElement> nodes =
element.Elements().Where(e => e.Name.LocalName == "items")
However this gets me all the "items" including the ones under "data" I don't want those.
If I do the following on my XML I do see the Names of the Elements displayed:
XElement element = XElement.Parse(data);
foreach (XElement node in element.Elements())
{
MessageBox.Show(node.Name.LocalName);
}
However when I do this I cannot see the node names under items at all - I've checked the XElement and it does have the node and when I output the names above it "items" shows up along with info and id!
foreach (XElement node in element.Elements("items"))
{
MessageBox.Show(node.Name.LocalName);
}
Assuming element is your <a:entry> element:
var ids = element.Element("items")
.Elements("item")
.Select(item => item.Element("id").Value);
The Element and Elements methods return only direct children, not all descendants, so it doesn't return the <items> element which is under <data>
I had a blank Namespace Declaration in my XML I hadn't noticed once I added this into my code it worked - forgot LINQ is very NameSpace oriented!
XNamespace ns = "http://example.org/namespace";
var ids = element.Element(ns + "items")
.Elements("item")
.Select(item => item.Element("id").Value);
Greeting,
What is the best practice to read all attributes from a child elements by ID attributes using C# in xml file listed down.
Thank you,
<?xml version="1.0" encoding="utf-8"?>
<WinDLN>
<Program ID="1" Name="CIS562" StartDate="9/8/2010 5:50:00 PM" EndDate="9/8/2010 9:15:00 PM" />
<Program ID="2" Name="CIS532" StartDate="10/8/2010 5:50:00 PM" EndDate="10/8/2010 9:15:00 PM" />
<Program ID="3" Name="ECE552" StartDate="6/8/2010 5:50:00 PM" EndDate="6/8/2010 9:15:00 PM" />
</WinDLN>
The following LINQ call should do the trick:
var attrs =
doc.Descendants("Program").First(prog =>
prog.Attribute("ID").Value == "2").Attributes();
The Descendants method gives you all elements (anywhere) in the XML document that are named "Program". Using First, you can get the first one that matches some specified predicate (e.g. has "ID" equal to "2"). Note that you can use FirstOrDefault if you want to get null when there is no such element. Finally, Attributes gives you a collection of all attribtues of the element.
I think that using LINQ to XML if you can is preferrable - you'll write the same code when working with XML or other data sources, so reading and writing the code is easy (once you learn LINQ).
There are many ways to do it, e.g. LINQ over XML. But using Xpath is definitely not dead yet:
class Program
{
static void Main(string[] args)
{
XmlDocument doc = new XmlDocument();
string xml = #"... your xml ";
doc.LoadXml(xml);
// Using SelectNodes with Xpath
XmlNodeList list = doc.SelectNodes("WinDLN/Program[#ID='2']");
Console.WriteLine(list.Count); // prints 1
list = doc.SelectNodes("WinDLN/Program[#ID]");
Console.WriteLine(list.Count); // prints 3 (selected all IDs)
}
}
What method you'll choose is most often a matter of taste, select the API you're most comfortable with.
I have been trying to parse this xml in c#
<schema uri=http://blah.com/schema >
<itemGroups>
<itemGroup description="itemGroup1 label="itemGroup1">
<items>
<item description="The best" itemId="1" label="Nutella"/>
<item description="The worst" itemId="2" label="Vegemite"/>
</items>
</itemGroup>
</itemGroups>
</schema>
\itemGroup1\Nutella-The best
\itemGroup1\Vegemite-The worst
Any help or direction would be appreciated.
XDocument xDoc = XDocument.Load(myXml); //load your XML from file or stream
var rows = xDoc.Descendants("item").Select(x => string.Format(
#"\{0}-{1}\{2}-{3}",
x.Ancestors("itemGroup").First().Attribute("description").Value,
x.Ancestors("itemGroup").First().Attribute("label").Value,
x.Attribute("label").Value,
x.Attribute("description").Value));
Let's break down what we're doing:
xDoc.Descendants("item") gets us all <item> elements in the entire document
Select(x => string.Format(format, args) projects each <item> we got from the last operation into whatever format we specify in the lambda. In this case, a formatted string.
In terms of the XML tree, we're "sitting at" the <item> level, so we need to roll back up the tree to get the data for the parent group using Ancestors. Since that method returns a sequence of elements, we know we want the first (nearest to us) so we can read its attribute.
Now you have an IEnumerable<string>, one for each <item> in your XML document and the information in the format you specified:
foreach(string row in rows)
{
Console.WriteLine(row);
}