Develop Reference

Getting XML node using XPath returns null

I am trying to get a node in a simple XML, but no matter what I try I always get null.
I am guessing that the issue is the namespace.
I am simply trying to get the value of the ID element, 331377697.
XmlDocument xmlDoc = new XmlDocument();
xmlDoc.Load("E:\\0323.xml");
XmlNamespaceManager manager = new XmlNamespaceManager(xmlDoc.NameTable);
manager.AddNamespace("cac", "http://xxxxxx Some URL XXXX");
manager.AddNamespace("cbc", "http://xxxxxx Some URL XXXX");
string query = "/StandardBusinessDocument/Invoice/cbc:ID";
XmlNode xmlNode = xmlDoc.SelectSingleNode(query, manager);
The XML:
<StandardBusinessDocument xmlns="http://www.unece.org/cefact/namespaces/StandardBusinessDocumentHeader">
<StandardBusinessDocumentHeader>
...
</StandardBusinessDocumentHeader>
<Invoice xmlns="urn:oasis:names:specification:ubl:schema:xsd:Invoice-2" xmlns:cac="urn:oasis:names:specification:ubl:schema:xsd:CommonAggregateComponents-2" xmlns:cbc="urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2" xmlns:ccts="urn:un:unece:uncefact:documentation:2"
...
</Invoice>
<cbc:UBLVersionID>2.1</cbc:UBLVersionID>
<cbc:CustomizationID>1234</cbc:CustomizationID>
<cbc:ProfileID>1234564</cbc:ProfileID>
<cbc:ID>331377697</cbc:ID>
<cbc:IssueDate>2017-03-23</cbc:IssueDate>
<cbc:InvoiceTypeCode listID="UNCL1001">380</cbc:InvoiceTypeCode>
<cbc:DocumentCurrencyCode listID="ISO4217">NOK</cbc:DocumentCurrencyCode>
<cac:OrderReference>
<cbc:ID>146136</cbc:ID>
</cac:OrderReference>
...

You must specify the exact namespaces.
Also you have to specify namespace prefixes for all elements in the XPath.
manager.AddNamespace("nsDoc", "http://www.unece.org/cefact/namespaces/StandardBusinessDocumentHeader");
manager.AddNamespace("nsInvoice", "urn:oasis:names:specification:ubl:schema:xsd:Invoice-2");
manager.AddNamespace("cbc", "urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2");
string query = "/nsDoc:StandardBusinessDocument/nsInvoice:Invoice/cbc:ID";
It's supposed to work.

XmlDocument XPath expression failing

I am using C# XmlDocument API.
I have the following XML:
<Node1>
<Node2>
<Node3>
</Node3>
</Node2>
</Node1>
I want to get Node3 as an XmlNode. But my code is returning null:
XmlDocument doc = new XmlDocument();
doc.Load(reader);
XmlNode root_node = doc.DocumentElement.SelectSingleNode("/Node1");
Log(root_node.OuterXml);
XmlNode test_node = root_node.SelectSingleNode("/Node2/Node3");
if (test_node == null)
Logger.Log.Error(" --- TEST NODE IS NULL --- ");
The log for root_node.OuterXml logs
<Node1><Node2><Node3>.....
But test_node returns null.
What is going wrong here?

Use the path "Node2/Node3" instead of "/Node2/Node3":
XmlNode test_node = root_node.SelectSingleNode("Node2/Node3");
In an XPath expression, a leading forward slash / represents the root of the document. The expression "/Node2/Node3" doesn't work because <Node2> isn't at the root of the document.

Use // instead of /, when you are selecting from the root node
XmlDocument doc = new XmlDocument();
doc.Load(reader);
XmlNode root_node = doc.DocumentElement.SelectSingleNode("/Node1");
XmlNode test_node = root_node.SelectSingleNode("//Node2/Node3");
Another option is to use full path to the node 3
XmlNode test_node = doc.DocumentElement.SelectSingleNode("/Node1/Node2/Node3");

You can simple call Descendants()
var xml= #"<Node1><Node2><Node3></Node3></Node2></Node1>";
XDocument doc = XDocument.Parse(xml);
var node = doc.Descendants("Node3");
or use Element() starting from Root
var node2= doc.Root.Element("Node2").Element("Node3");
or use XPathSelectElement()
var node3= doc.XPathSelectElement("/Node1/Node2/Node3");

C# select node from XML

I have this code in C#, I need to get a Cube nodes, but my list of nodes is empty..
string url = #"http://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml";
XmlDocument xmlDoc = new XmlDocument();
xmlDoc.Load(url);
XmlNamespaceManager manager = new XmlNamespaceManager(xmlDoc.NameTable);
manager.AddNamespace("gesmes", "http://www.gesmes.org/xml/2002-08-01");
XmlNodeList nodes = xmlDoc.SelectNodes("/gesmes:Envelope/Cube", manager);
What am I doing wrong?

There is a default namespace http://www.ecb.int/vocabulary/2002-08-01/eurofxref which you will need to register, to access the Cube element.
Otherwise, the XPath expression tries to find an un-namespaced Cube element, which doesn't exist in the document. XPath has no concept of a default namespace.
string url = #"http://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml";
XmlDocument xmlDoc = new XmlDocument();
xmlDoc.Load(url);
XmlNamespaceManager manager = new XmlNamespaceManager(xmlDoc.NameTable);
manager.AddNamespace("gesmes", "http://www.gesmes.org/xml/2002-08-01");
manager.AddNamespace("default", "http://www.ecb.int/vocabulary/2002-08-01/eurofxref");
XmlNodeList nodes = xmlDoc.SelectNodes("/gesmes:Envelope/default:Cube", manager);
this will access the Cube child directly under the gesmes:Envelope. Depending what you want to achieve, you may want to use one of the following XPath expressions instead:
/gesmes:Envelope/default:Cube/default:Cube/default:Cube
/gesmes:Envelope//default:Cube[#currency]
/gesmes:Envelope//default:Cube[#time]/default:Cube

I need to convert an XML string into an XmlElement

I'm looking for the simplest way to convert a string containing valid XML into an XmlElement object in C#.
How can you turn this into an XmlElement?
<item><name>wrench</name></item>

Use this:
private static XmlElement GetElement(string xml)
{
XmlDocument doc = new XmlDocument();
doc.LoadXml(xml);
return doc.DocumentElement;
}
Beware!!
If you need to add this element to another document first you need to Import it using ImportNode.

Suppose you already had a XmlDocument with children nodes, And you need add more child element from string.
XmlDocument xmlDoc = new XmlDocument();
// Add some child nodes manipulation in earlier
// ..
// Add more child nodes to existing XmlDocument from xml string
string strXml =
#"<item><name>wrench</name></item>
<item><name>screwdriver</name></item>";
XmlDocumentFragment xmlDocFragment = xmlDoc.CreateDocumentFragment();
xmlDocFragment.InnerXml = strXml;
xmlDoc.SelectSingleNode("root").AppendChild(xmlDocFragment);
The Result:
<root>
<item><name>this is earlier manipulation</name>
<item><name>wrench</name></item>
<item><name>screwdriver</name>
</root>

Use XmlDocument.LoadXml:
XmlDocument doc = new XmlDocument();
doc.LoadXml("<item><name>wrench</name></item>");
XmlElement root = doc.DocumentElement;
(Or in case you're talking about XElement, use XDocument.Parse:)
XDocument doc = XDocument.Parse("<item><name>wrench</name></item>");
XElement root = doc.Root;

You can use XmlDocument.LoadXml() to do this.
Here is a simple examle:
XmlDocument xmlDoc = new XmlDocument();
xmlDoc.LoadXml("YOUR XML STRING");

I tried with this snippet, Got the solution.
// Sample string in the XML format
String s = "<Result> No Records found !<Result/>";
// Create the instance of XmlDocument
XmlDocument doc = new XmlDocument();
// Loads the XML from the string
doc.LoadXml(s);
// Returns the XMLElement of the loaded XML String
XmlElement xe = doc.DocumentElement;
// Print the xe
Console.out.println("Result :" + xe);
If any other better/ efficient way to implement the same, please let us know.
Thanks & Cheers

Change XML root element name

I have XML stored in string variable:
<ItemMasterList><ItemMaster><fpartno>xxx</fpartno><frev>000</frev><fac>Default</fac></ItemMaster></ItemMasterList>
Here I want to change XML tag <ItemMasterList> to <Masterlist>. How can I do this?

System.Xml.XmlDocument and the associated classes in that same namespace will prove invaluable to you here.
XmlDocument doc = new XmlDocument();
doc.LoadXml(yourString);
XmlDocument docNew = new XmlDocument();
XmlElement newRoot = docNew.CreateElement("MasterList");
docNew.AppendChild(newRoot);
newRoot.InnerXml = doc.DocumentElement.InnerXml;
String xml = docNew.OuterXml;

I know i am a bit late, but just have to add this answer as no one seems to know about this.
XDocument doc = XDocument.Parse("<ItemMasterList><ItemMaster><fpartno>xxx</fpartno><frev>000</frev><fac>Default</fac></ItemMaster></ItemMasterList>");
doc.Root.Name = "MasterList";
Which returns the following:
<MasterList>
<ItemMaster>
<fpartno>xxx</fpartno>
<frev>000</frev>
<fac>Default</fac>
</ItemMaster>
</MasterList>

You can use LINQ to XML to parse the XML string, create a new root and add the child elements and attributes of the original root to the new root:
XDocument doc = XDocument.Parse("<ItemMasterList>...</ItemMasterList>");
XDocument result = new XDocument(
new XElement("Masterlist", doc.Root.Attributes(), doc.Root.Nodes()));

Using the XmlDocument way, you can do this as follows (and keep the tree intact):
XmlDocument oldDoc = new XmlDocument();
oldDoc.LoadXml("<ItemMasterList><ItemMaster><fpartno>xxx</fpartno><frev>000</frev><fac>Default</fac></ItemMaster></ItemMasterList>");
XmlNode node = oldDoc.SelectSingleNode("ItemMasterList");
XmlDocument newDoc = new XmlDocument();
XmlElement ele = newDoc.CreateElement("MasterList");
ele.InnerXml = node.InnerXml;
If you now use ele.OuterXml is will return: (you you just need the string, otherwise use XmlDocument.AppendChild(ele) and you will be able to use the XmlDocument object some more)
<MasterList>
<ItemMaster>
<fpartno>xxx</fpartno>
<frev>000</frev>
<fac>Default</fac>
</ItemMaster>
</MasterList>

As pointed by Will A, we can do it that way but for case where InnerXml equals the OuterXml the following solution will work out:
// Create a new Xml doc object with root node as "NewRootNode" and
// copy the inner content from old doc object using the LastChild.
XmlDocument docNew = new XmlDocument();
XmlElement newRoot = docNew.CreateElement("NewRootNode");
docNew.AppendChild(newRoot);
// The below line solves the InnerXml equals the OuterXml Problem
newRoot.InnerXml = oldDoc.LastChild.InnerXml;
string xmlText = docNew.OuterXml;