Develop Reference

C# XML child node of similar sibling

I'm trying to modify an XML document that we didn't create initially. Snippit from XML is below:
<DEALS>
<DEAL>
<LOANS>
<LOAN LoanRoleType="SubjectLoan">
<BUYDOWN>
<BUYDOWN_RULE>
<BuydownInformation>0</BuydownInformation>
</BUYDOWN_RULE>
</BUYDOWN>
</LOAN>
<LOAN LoanRoleType="SubjectLoan">
<LOAN_IDENTIFIERS>
<LOAN_IDENTIFIER>
...
</LOAN_IDENTIFIER>
<LOAN_IDENTIFIER>
<SellerLoanIdentifier>1234567890</SellerLoanIdentifier>
</LOAN_IDENTIFIER>
</LOAN_IDENTIFIERS>
</LOAN>
</LOANS>
</DEAL>
<DEAL>
...Same format as above...
</DEAL>
</DEALS>
The first LOAN element of each DEAL will never contain LOAN_IDENTIFIERS. I need to get the SellerLoanIdentifier's InnerText, and then put it into <BuydownInformation> of the first LOAN element. I've tried nested loops and can't seem to get it to differentiate between the two LOAN elements (the second loop isn't even seeing the LOAN elements). I'm thinking it also might have to do with the fact that they both carry the exact same attribute but can't find anything online up to this point to help.
XmlDocument xmlExport = new XmlDocument();
xmlExport.Load(fileDestination);
string loanNumber = "";
XmlNodeList loan_XMLDeals = xmlExport.GetElementsByTagName("DEAL");
Logger.WriteDebug("Found " + loan_XMLDeals.Count + " Deals");
foreach (XmlNode loan_XMLDeal in loan_XMLDeals)
{
XmlNodeList loan_XMLLoans = loan_XMLDeal.SelectNodes("LOAN");
Logger.WriteDebug("Found " + loan_XMLLoans.Count + " Loan categories");
foreach (XmlNode loan_XMLCategory in loan_XMLLoans)
{
if(loan_XMLCategory.SelectSingleNode("SellerLoanIdentifier") != null)
{
loanNumber = loan_XMLCategory.SelectSingleNode("SellerLoanIdentifier").ToString();
Logger.WriteDebug("Got loan number " + loanNumber);
}
}
}

This becomes a lot easier with linq to xml. This means ditching the (old) XmlDocument and replacing it with the friendlier XDocument.
Instead of searching the whole document for the target, you need to start from the context of where you found the SellerLoanIdentifier. You can walk back up to the LOAN element, find its previous sibling, then search that for the BuydownInformation. Because this was all scoped within a single LOANS entry, you can be sure you're targeting the right element.
So...
var doc = XDocument.Load(fileDestination);
//we're going to select a sequence of items that contain 2 values...
//the element we want to change and the value we want to store in it
var changes= doc.Root
.Elements("DEAL")
.Descendants("SellerLoanIdentifier")
//from each SellerLoanIdentifier in DEAL elements
.Select(e => new{
//the node we want to change
//in this case we get the parent LOAN
//element, take the last of the elements
//that precede it in the document
//(e.g. the previous sibling which
//contains the target node)
//and find in it a descendant of type
//BuydownInformation
nodeToChange = e.Ancestors("LOAN")
.Single()
.ElementsBeforeSelf()
.Last()
.Descendants("BuydownInformation")
.Single(),
//the string value of the current element
val = (string)e
});
//then apply the changes back to the document
foreach(var change in changes)
{
change.nodeToChange.Value = change.val;
}
var newXmlString = doc.ToString();
There are assumptions here about the shape of your data that may not hold true, but it should be relatively easy to modify.

Try this simple XML Linq code
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;
using System.Xml.Linq;
namespace ConsoleApplication1
{
class Program
{
const string FILENAME = #"c:\temp\test.xml";
static void Main(string[] args)
{
XDocument doc = XDocument.Load(FILENAME);
List<XElement> loans = doc.Descendants("LOANS").ToList();
foreach (XElement loan in loans)
{
string sellerLoanIdentifier = (string)loan.Descendants("SellerLoanIdentifier").FirstOrDefault();
XElement buydownInformation = loan.Descendants("BuydownInformation").FirstOrDefault();
buydownInformation.Value = sellerLoanIdentifier;
}
}
}
}

Reading Sub-Elements (child nodes) with XMLreader using C#

First: This is NOT a duplicate of Reading Child Nodes with XMLReader
(Not the same language, Couldn't get it to help me).
I'm pretty new to XMLreading, I am trying to reach the Sub Element of a specific Element but I am having hard time reaching it, here is an example:
The XML element:
<Group ExerciseNumber="0" Name="R33-IOS1_IOS1" ExerciseName="Unallocated" Status="offline" StatusStatistics="0/1">
<Clients>
<Client ClientName="R33-IOS1_IOS1" MachineName="R33-IOS1" ClientType="HC0" ClientStatus="Disconnected" />
</Clients>
<GroupAppendedData GroupID="201" Type="IOS" DomeType="None" ConnectedTo="" ForceType="Enemy" />
</Group>
I am trying to reach the "Client" element from the specific "Group" element, This is my C# code:
while (reader.Read())
{
if (reader.Name.Equals("Group"))
{
name = reader.GetAttribute("Name");
// Now I need to reach the specific "MachineName" attribute of the "Client" sub-element but don't know how.
}
}
reader.Close();
Notes:
It's important that the client element reading will be in the same loop iteration (if possible, if not I will have to think of another design for my generating class).
*Editing the XML is not an option.
Thank you.

LINQ to XML would be easier to use than XmlReader, this will give you machine names for all Clients in the document:
var machineNames = XElement.Parse("data.xml")
.Descendants("Client")
.Select(client => client.Attribute("MachineName").Value);
Edit - this returns both names in every iteration:
var query = XElement.Load("data.xml")
.Descendants("Client")
.Select(client => new {
MachineName = client.Attribute("MachineName").Value,
GroupName = client.Ancestors("Group").Select(g => g.Attribute("Name").Value).First()
});
foreach (var x in query)
Console.WriteLine($"GroupName: {x.GroupName}, MachineName: {x.MachineName}");

As suggested, unless you have a very good reason to use XmlReader then using a higher level API such as LINQ to XML would be preferred.
Here's a solution using query syntax:
var clients = from #group in doc.Descendants("Group")
let groupName = (string) #group.Attribute("Name")
from client in #group.Descendants("Client")
select new
{
GroupName = groupName,
ClientName = (string) client.Attribute("ClientName"),
MachineName = (string) client.Attribute("MachineName"),
};
See this fiddle for a working example.

try ReadFrom() method in xml linq
while (reader.Read())
{
if (reader.Name.Equals("Group"))
{
XElement group = (XElement)XDocument.ReadFrom(reader);
}
}
reader.Close();​

LINQ: How to return all child elements?

For an application I am working on, I have to display data from an XML File. There's a few transformations being done, but eventually the end result will be displayed in a treeview. When a user then clicks on a node, I want to pop up the details in a listview.
When no node has been selected, I basically use LINQ to grab the details of the first item I encounter.
Here's a simplified version of my XML
<root>
<parent label="parent1">
<child label="child1">
<element1>data</element1>
<element2>data</element2>
...
</child>
<child label="child2">
<element1>data</element1>
<element2>data</element2>
...
</child>
</parent>
</root>
And here's the code used to grab it (After selecting the parent-node that the treeview has been set to by means of an XPAthSelectStatement):
protected void listsSource_Selecting(object sender, LinqDataSourceSelectEventArgs e)
{
XElement rootElement = XElement.Load(MapPath(TreeSource.DataFile));
rootElement = rootElement.XPathSelectElement("//parent[#label='parent1']");
XElement parentElement;
parentElement = rootElement;
var query = (from itemElement in parentElement.Descendants("child")
select new
{
varElement1 = itemElement.Element("element1").Value,
varElement2 = itemElement.Element("element2").Value,
...
}).Take(1);
e.result = Query;
}
This works a treat, and I can read out the varElement1 and varElement2 values from there. However, when I try and implement a similar mechanism for when the user actually did select a node, I seem to run into a wall.
My approach was to use another XPatchSelectStatement to get to the actual node:
parentElement = rootElement.XPathSelectElement("//child[#label='" + tvwChildren.SelectedNode.Text + "']");
But I am kind of stumped on how to now get a proper LINQ query built up to read in all elements nested under the child node. I tried using parentElement.Elements(), but that was yielding an error. I also looked at using Nodes(), but with similar results.
I suppose I could use a foreach loop to access the nodes, but then I'm not sure how to get the results into a LINQ query so I can return the same e.Result = query back.
I'm fairly new to LINQ, as you might have guessed, so any hints would be very much appreciated.

Here's the query that will give you the child element (given that there is only one child element with the specified label):
var childElement = rootNode.Descendants("child")
.Single(e=>e.Attribute("label").Value == "child1");
If you have more than one child elements with label="child1" but those elements are under different parent elements you can use the same approach to get first the parent element and then the child element.
Having the above, you can use this query to get all element nodes under the child node:
var elements = childElement.Descendants().Select(e=>e.Value);

I think data binding is much easier in this case.
XDocument doc = XDocument.Load(filePath);
if (doc.Root == null)
{
throw new ApplicationException("invalid data");
}
tvwChildren.Source=doc;
But if you want in this way hope following one helps(not the exact solution)
XElement root = XElement.Load("Employees.xml");
TreeNode rootNode = new TreeNode(root.Name.LocalName);
treeView1.Nodes.Add(rootNode);
foreach(XElement employee in root.Elements())
{
TreeNode employeeNode = new TreeNode("Employee ID :" + employee.Attribute("employeeid").Value);
rootNode.Nodes.Add(employeeNode);
if (employee.HasElements)
{
foreach(XElement employeechild in employee.Descendants())
{
TreeNode childNode = new TreeNode(employeechild.Value);
employeeNode.Nodes.Add(childNode);
}
}
}
And you can try Resharper tool for create better linq statements. It shows possible ones and you can easily convert each for,foreach loops into linq statements.

I'm not entirely sure I understand what you're trying to do, but it sounds like it could be this:
var data =
from p in xml.Root.Elements("parent")
where p.Attribute("label").Value == "parent1"
from c in p.Elements("child")
where c.Attribute("label").Value == "child2"
from d in c.Elements()
select d.Value;
Let me know if that helps.

Using this Xml library you can write your XPath like:
XElement child = rootElement.XPathElement(
"//parent[#label={0}]/child[#label={1}]", "parent1", "child2");

XPathSelectElements returns null

Load function is already defined in xmlData class
public class XmlData
{
public void Load(XElement xDoc)
{
var id = xDoc.XPathSelectElements("//ID");
var listIds = xDoc.XPathSelectElements("/Lists//List/ListIDS/ListIDS");
}
}
I'm just calling the Load function from my end.
XmlData aXmlData = new XmlData();
string input, stringXML = "";
TextReader aTextReader = new StreamReader("D:\\test.xml");
while ((input = aTextReader.ReadLine()) != null)
{
stringXML += input;
}
XElement Content = XElement.Parse(stringXML);
aXmlData.Load(Content);
in load function,im getting both id and and listIds as null.
My test.xml contains
<SEARCH>
<ID>11242</ID>
<Lists>
<List CURRENT="true" AGGREGATEDCHANGED="false">
<ListIDS>
<ListID>100567</ListID>
<ListID>100564</ListID>
<ListID>100025</ListID>
<ListID>2</ListID>
<ListID>1</ListID>
</ListIDS>
</List>
</Lists>
</SEARCH>

EDIT: Your sample XML doesn't have an id element in the namespace with the nss alias. It would be <nss:id> in that case, or there'd be a default namespace set up. I've assumed for this answer that in reality the element you're looking for is in the namespace.
Your query is trying to find an element called id at the root level. To find all id elements, you need:
var tempId = xDoc.XPathSelectElements("//nss:id", ns);
... although personally I'd use:
XDocument doc = XDocument.Parse(...);
XNamespace nss = "http://schemas.microsoft.com/SQLServer/reporting/reportdesigner";
// Or use FirstOrDefault(), or whatever...
XElement idElement = doc.Descendants(nss + "id").Single();
(I prefer using the query methods on LINQ to XML types instead of XPath... I find it easier to avoid silly syntax errors etc.)
Your sample code is also unclear as you're using xDoc which hasn't been declared... it helps to write complete examples, ideally including everything required to compile and run as a console app.

I am looking at the question 3 hours after it was submitted and 41 minutes after it was (last) edited.
There are no namespaces defined in the provided XML document.
var listIds = xDoc.XPathSelectElements("/Lists//List/ListIDS/ListIDS");
This XPath expression obviously doesn't select any node from the provided XML document, because the XML document doesn't have a top element named Lists (the name of the actual top element is SEARCH)
var id = xDoc.XPathSelectElements("//ID");
in load function,im getting both id and and listIds as null.
This statement is false, because //ID selects the only element named ID in the provided XML document, thus the value of the C# variable id is non-null. Probably you didn't test thoroughly after editing the XML document.
Most probably the original ID element belonged to some namespace. But now it is in "no namespace" and the XPath expression above does select it.

string xmldocument = "<response xmlns:nss=\"http://schemas.microsoft.com/SQLServer/reporting/reportdesigner\"><action>test</action><id>1</id></response>";
XElement Content = XElement.Parse(xmldocument);
XPathNavigator navigator = Content.CreateNavigator();
XmlNamespaceManager ns = new XmlNamespaceManager(navigator.NameTable);
ns.AddNamespace("nss", "http://schemas.microsoft.com/SQLServer/reporting/reportdesigner");
var tempId = navigator.SelectSingleNode("/id");

The reason for the null value or system returned value is due to the following
var id = xDoc.XPathSelectElements("//ID");
XpathSElectElements is System.xml.linq.XElment which is linq queried date. It cannot be directly outputed as such.
To Get individual first match element
use XPathSelectElement("//ID");
You can check the number of occurrences using XPathSelectElements as
var count=xDoc.XPathSelectElements("//ID").count();
you can also query the linq statement as order by using specific conditions
Inorder to get node value from a list u can use this
foreach (XmlNode xNode in xDoc.SelectNodes("//ListIDS/ListID"))
{
Console.WriteLine(xNode.InnerText);
}
For Second list you havnt got the value since, the XPath for list items is not correct

A simple question about LINQ to XML

<root xmlns:h="http://www.w3.org/TR/html4/"
xmlns:f="http://www.w3schools.com/furniture">
<h:table>
<h:tr>
<h:td>Apples</h:td>
<h:td>Bananas</h:td>
</h:tr>
</h:table>
<f:table>
<f:name>African Coffee Table</f:name>
<f:width>80</f:width>
<f:length>120</f:length>
</f:table>
</root>
I am trying to practice LinqToXml but i can't figure out what i wanted.Simply how can i query table elements which has h or f namespace ?
This was what i tried .Also i tried different ones but didn't work.
var query = from item in XDocument.Parse(xml).Elements(ns + "table")
select item;

This won't work because you're missing the root element from your query. This would work:
XNamespace ns = "http://www.w3schools.com/furniture";
var query = XDocument.Parse(xml).Element("root").Elements(ns + "table");
Now if the problem is that you want to find all "table" elements regardless of the namespace, you'd need something like this:
var query = XDocument.Parse(xml)
.Element("root")
.Elements()
.Where(element => element.Name.LocalName == "table");
(EDIT: As noted, you could use XDocument.Root to get to the root element if you want to. The important point is that trying to get to the table element directly from the document node itself won't work.)

Namespace prefixes are not guaranteed to be a particular letter or string. The best approach would be to search by the qualified namespace.
This would get all direct child nodes of XElement xml where the namespace is uri:namespace...
var selectedByNamespace = from element in xml.Elements()
where element.Name.NamespaceName == "uri:namespace"
select element;
Another option would be to select the elements based on the fully qualified name.
var ns = "{uri:namespace}";
var selectedElements = xml.Elements(ns + "table");