Develop Reference

How to Get XML Element by It's 'Value' using XML C# SDK

I have this snippt of XML
<unit class="xxx.xxx.xxx" id="382">
<customId>000</customId>
<description>kg</description>
<key>22452</key>
<Description>Kilogramm</Description>
</unit>
how to get the node 'unit' or parnet of the key element using the value of an element. For instance
i have the value of key element above [22452] and it's Uniqe inside the xml-File.
what i am trying to do getting value of customid [000] of that specific tag.
what i did:
var doc = new XmlDocument();
doc.Load(stream); // stream from xml-file
var key = doc.SelectSingleNode(//key/[text()='" + 22452+ "']"); // that i am not sure about it.
var customId = key.InnerText("customId");

For this kind of query you could either find the node and than navigate to the parent.
Or use XPath:
var unitElemnt = doc.SelectSingleNode("//unit[key = '22452']");
(Assuming I've remembered the XPath to match an element's text content correctly.)
This gets a reference to the <unit> element, by using a relative path to the <key> element in the predicate of the XPath expression.
Generally better to avoid // in XPath for performance, but would need full document structure to do that.

For this you can use Linq to Xml queries.
XElement units = XElement.Load("./Test.xml");
XElement unit = (from item in units.Descendants("unit")
where item.Element("key").Value == "22455"
select item).FirstOrDefault();
string customId = unit.Element("customId").Value;
supposing your xml file look like :
<?xml version="1.0" encoding="utf-8"?>
<units>
<unit class="xxx.xxx.xxx" id="385">
<customId>003</customId>
<description>kg</description>
<key>22455</key>
<Description>Kilogramm</Description>
</unit>
<unit class="xxx.xxx.xxx" id="386">
<customId>004</customId>
<description>kg</description>
<key>22456</key>
<Description>Kilogramm</Description>
</unit>
</units>
for more reading check Microsoft Linq to Xml Docs

Using XDocument to convert selected node to string

I have the following XML sample.
<?xml version="1.0" encoding="utf-8"?>
<GlobalResponses>
<Filters>
<FilterId>11</FilterId>
<FilterId>5</FilterId>
<FilterId>10</FilterId>
</Filters>
<Responses>
<Response>
<Name>Bob</Name>
</Response>
<Response>
<Name>Jim</Name>
</Response>
<Response>
<Name>Steve</Name>
</Response>
</Responses>
</GlobalResponses>
Using XDocument, how can I get only the <Responses> parent and also child nodes, and convert them to a string variable. I looked at XDocument Elements and Descendants, but by calling oXDocument.Descendants("Responses").ToString(); didn't work.
Do I have to iterate over all of the XElements checking each one and then appending to a string variable ?

Function Descendants returns enumeration of XElement, so you need to select specific element.
If you want to get XML element with all the child nodes, you can use:
// assuming that you only have one tag Responses.
oXDocument.Descendants("Responses").First().ToString();
The result is
<Responses>
<Response>
<Name>Bob</Name>
</Response>
<Response>
<Name>Jim</Name>
</Response>
<Response>
<Name>Steve</Name>
</Response>
</Responses>
If you want to get child nodes and concatenate them to single string you can use
// Extract list of names
var names = doc.Descendants("Responses").Elements("Response").Select(x => x.Value);
// concatenate
var result = string.Join(", ", names);
The result is Bob, Jim, Steve

The Descendants() method takes input the element name and it will return you a collection of nodes and from those you then further need to get the elements you are interested in.
You can use linq with XDocument to extract the information. For example, the following code with extract the Name element value from each Response node and prints out :
var nodes = from response in Doc.Descendants("Response")
select response.Element("Name").Value;
foreach(var node in nodes)
Console.WriteLine(node);
Here above Doc.Descendants("Response") will fetch all the <Response> elements and then we are using response.Element("Name") to fetch the <Element> tag for each <Response> element and then using .Value property we get the value between the tag.
See this working DEMO fiddle.

Select an XML node with a given child value and update a different child element

I have the following xml file:
<LabelImageCreator xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<PrintFieldList>
<PrintFieldDefinition>
<FieldName>Facility</FieldName>
<DataParameterName>Address</DataParameterName>
<FieldFont>
<FontName>Arial</FontName>
<FontSize>10</FontSize>
<FontStyle>Regular</FontStyle>
</FieldFont>
<CurrentDataValue/>
</PrintFieldDefinition>
<PrintFieldDefinition>
<FieldName>Country</FieldName>
<DataParameterName>CountryofOrigin</DataParameterName>
<WrapField>false</WrapField>
<FieldFont>
<FontName>Arial</FontName>
<FontSize>8</FontSize>
<FontStyle>Regular</FontStyle>
</FieldFont>
<CurrentDataValue/>
<TextPrefix>Produce of </TextPrefix>
</PrintFieldDefinition>
<PrintFieldList>
<LabelImageCreator>
I have to select the attribute with field name Facilityand add the address(eg: No 2546, Gorrge street, California, US) to <CurrentDataValue/> field and save it.
I tried with the below code,
XmlDocument xmlDocument = new XmlDocument();
xmlDocument.Load(path);
var node = xmlDocument.DocumentElement.SelectSingleNode(
"./PrintFieldList/PrintFieldDefinition[#FieldName='Facility']");
Above code while debuging it is not working. Can any one guide me how to select and update the xml attribute.

A couple of minor issues:
You need to start from the root element LabelImageCreator
FieldName is an element, not an attribute, so hence FieldName and not #FieldName
The closing tags on the Xml Document don't match up.
If you want to select the child element CurrentDataValue of parent PrintFieldDefinition with the child FieldName with value Facility:
var node = xmlDocument.DocumentElement.SelectSingleNode(
"/LabelImageCreator/PrintFieldList/PrintFieldDefinition[FieldName='Facility']/CurrentDataValue");
Changing the value is then simply:
node.InnerText = "No 2546, Gorrge street, California, US";

I would use XDocument instead of XmlDocument (it allows you to use linq which in my opinion, is easier than using xpath).
You can find your node like this and I believe you can update them too (first search and get the value, then search again and update on the other node).
Example:
var nodesMatching = from node in myXDocument.Descendants()
where node.Name.LocalName.Equals("mySearchNode")
select node;
var node = nodesMatching.FirstOrDefault();

Locating a value in XML

I have an xml file loaded into an XDocument that I need to extract a value from, and I'm not sure of the best way to do it. Most of the things I'm coming up with seem to be overkill or don't make good use of xml rules. I have the following snippet of xml:
<entry>
<observation classCode="OBS" moodCode="EVN">
<templateId root="2.16.840.1.113883.10.20.6.2.12" />
<code code="121070" codeSystem="1.2.840.10008.2.16.4" codeSystemName="DCM" displayName="Findings">
</code>
<value xsi:type="ED">
<reference value="#121071">
</reference>
</value>
</observation>
</entry>
There can be any number of <entry> nodes, and they will all follow a similar pattern. The value under the root attribute on the templateId element contains a known UID that identifies this entry as the one I want. I need to get the reference value.
My thought is to find the correct templateID node, back out to the observation node, find <valuexsi:type="ED"> and then get the reference value. This seems overly complex, and I am wondering if there is another way to do this?
EDIT
The xml I receive can sometimes have xml nested under the same node name. In other words, <observation> may be located under another node named <observation>.

You have problems, because your document uses Namespaces, and your query is missing them.
First of all, you have to find xsi namespace declaration somewhere in your XML (probably in the most top element).
It will look like that:
xmlns:xsi="http://test.namespace"
The, take the namespace Uri and create XNamespace instance according to it's value:
var xsi = XNamespace.Get("http://test.namespace");
And use that xsi variable within your query:
var query = from o in xdoc.Root.Element("entries").Elements("entry").Elements("observation")
let tId = o.Element("templateId")
where tId != null && (string)tId.Attribute("root") == "2.16.840.1.113883.10.20.6.2.12"
let v = o.Element("value")
where v != null && (string)v.Attribute(xsi + "type") != null
let r = v.Element("reference")
where r != null
select (string)r.Attribute("value");
var result = query.FirstOrDefault();
I have tested it for following XML structure:
<root xmlns:xsi="http://test.namespace">
<entries>
<entry>
<observation classCode="OBS" moodCode="EVN">
<templateId root="2.16.840.1.113883.10.20.6.2.12" />
<code code="121070" codeSystem="1.2.840.10008.2.16.4" codeSystemName="DCM" displayName="Findings">
</code>
<value xsi:type="ED">
<reference value="#121071">
</reference>
</value>
</observation>
</entry>
</entries>
</root>
The query returns #121071 for it.
For your input XML you will probably have to change first line of query:
from o in xdoc.Root.Element("entries").Elements("entry").Elements("observation")
to match <observation> elements from your XML structure.

Would something along the lines of the following help?
XDocument xdoc = GetYourDocumentHere();
var obsvlookfor =
xdoc.Root.Descendants("observation")
.SingleOrDefault(el =>
el.Element("templateId")
.Attribute("root").Value == "root value to look for");
if (obsvlookfor != null)
{
var reference = obsvlookfor
.Element("value")
.Element("reference").Attribute("value").Value;
}
My thought is as follows:
Pull out all the observation elements in the document
Find the only one (or null) where the observation's templateId element has a root attribute you're looking for
If you find that observation element, pull out the value attribute against the reference element which is under the value element.

You might have to include the Namespace in your LINQ. To retrieve that you would do something like this:
XNamespace ns = xdoc.Root.GetDefaultNamespace();
Then in your linq:
var obsvlookfor = xdoc.Root.Descendants(ns + "observation")
I know I had some issues retrieving data once without this. Not saying its the issue just something to keep in mind particularly if your XML file is very in depth.

Load info from xml, save related (changed) info using c#

Friends,
My school project is having an xml data file:
<patients>
<patient>
<regNo>2012/Mar/003</regNo>
<name>Jhon</name>
<add>Somewhere</add>
<mobile>0000</mobile>
.
.
.
<stay>2</stay>
<costofroom>100</costofroom>
<total>200</total>
</patient>
</patients>
My Windowsform "EditPatients_Load" is able to fetch all info of patient Jhon, and now let's assume that the Admin needs to change some information in the form & resubmit.
Then how to write back all values to Jhon's account in the same xml
file????
I'm not able to makeup the logical code, even if I check the node if (patients.paptient.name = "nameComboBox.text").... how to make sure that I'm writing other values on proper place?
Rgrdz,

Try this:
//string xml =
//#"<patients><patient><regNo>2012/Mar/003</regNo><name>Jhon</name><add>Somewhere
//</add><mobile>0000</mobile><stay>2</stay><costofroom>100</costofroom><total>200</total>
//</patient></patients>";
XDocument xmlDoc = XDocument.Load(#"c:\abc.xml");
var items = (from item in xmlDoc.Descendants("patient")
where item.Element("name").Value == "Jhon"
select item);
if (items.Count() > 0)
{
var item = items.First();
item.SetElementValue("add", "New New Address");
xmlDoc.Save(#"c:\abc.xml", SaveOptions.None);
}
You can get single element using
var item = (from item in xmlDoc.Descendants("patient")
where item.Element("name").Value == "Jhon"
select item).FirstOrDefault();
then update it using SetElementValue() method.
//Updated Xml
<?xml version="1.0" encoding="utf-8"?>
<patients>
<patient>
<regNo>2012/Mar/003</regNo>
<name>Jhon</name>
<add>New Address</add>
<mobile>0000</mobile>
<stay>2</stay>
<costofroom>100</costofroom>
<total>200</total>
</patient>
</patients>
Reference:
Update XML with C# using Linq

I would take the xml serialization/deserialization route to solve this:
http://support.microsoft.com/kb/815813
How to Deserialize XML document
That way you can work with objects and not have to parse xml files manually.

If you're using .NET 3.5 onward you can use the XDocument class like the following. I'm assuming your content is in a .xml file.
XDocument xdoc = XDocument.Load(#"C:\Tmp\test.xml");
//this would ensure you get the right node and set its text content/value
xdoc.Element("patients")
.Element("patient").Element("add").Value = "some new address?";
xdoc.Save(#"C:\Tmp\test.xml");
The file test.xml would change to:
<patients>
<patient>
<regNo>2012/Mar/003</regNo>
<name>Jhon</name>
<add>some new address?</add>
<mobile>0000</mobile>
<stay>2</stay>
<costofroom>100</costofroom>
<total>200</total>
</patient>
</patients>