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C# Read XML with multiple variable namespaces

I have to read some tags and attributes from an XML that has a defined structure but since those files can be generated from different sources, they can have different namespaces and prefixes.
This is the first XML sample
<Order xmlns="urn:oasis:names:specification:ubl:schema:xsd:Order-2" xmlns:cac="urn:oasis:names:specification:ubl:schema:xsd:CommonAggregateComponents-2" xmlns:cbc="urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2" xmlns:xs="http://www.w3.org/2001/XMLSchema">
<cbc:UBLVersionID>2.1</cbc:UBLVersionID>
<cbc:CustomizationID>urn:www.cenbii.eu:transaction:biitrns001:ver2.0:extended:urn:www.peppol.eu:bis:peppol3a:ver2.0:extended:urn:www.ubl-italia.org:spec:ordine:ver2.1</cbc:CustomizationID>
<cbc:ID>ORD-001</cbc:ID>
<cbc:IssueDate>2016-10-01</cbc:IssueDate>
<cbc:OrderTypeCode listID="UNCL1001">221</cbc:OrderTypeCode>
<cac:ValidityPeriod>
<cbc:EndDate>2024-10-19</cbc:EndDate>
</cac:ValidityPeriod>
<cac:BuyerCustomerParty>
<cac:Party>
<cbc:EndpointID schemeID="IT:IPA">ITAK12MH</cbc:EndpointID>
<cac:PartyIdentification>
<cbc:ID schemeID="IT:VAT">01567570254</cbc:ID>
</cac:PartyIdentification>
<cac:PartyName>
<cbc:Name>A Custom Name</cbc:Name>
</cac:PartyName>
</cac:Party>
</cac:BuyerCustomerParty>
</Order>
This is the second XML sample with different namespaces and prefixes, but same structure (tags, attributes).
<ns10:Order xmlns="urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2" xmlns:ns2="urn:oasis:names:specification:ubl:schema:xsd:CommonExtensionComponents-2" xmlns:ns3="urn:oasis:names:specification:ubl:schema:xsd:CommonAggregateComponents-2" xmlns:ns4="http://www.w3.org/2000/09/xmldsig#" xmlns:ns5="http://uri.etsi.org/01903/v1.3.2#" xmlns:ns6="urn:oasis:names:specification:ubl:schema:xsd:SignatureBasicComponents-2" xmlns:ns7="urn:oasis:names:specification:ubl:schema:xsd:SignatureAggregateComponents-2" xmlns:ns8="http://uri.etsi.org/01903/v1.4.1#" xmlns:ns9="urn:oasis:names:specification:ubl:schema:xsd:CommonSignatureComponents-2" xmlns:ns10="urn:oasis:names:specification:ubl:schema:xsd:Order-2">
<UBLVersionID>2.1</UBLVersionID>
<CustomizationID>urn:www.cenbii.eu:transaction:biitrns001:ver2.0:extended:urn:www.peppol.eu:bis:peppol3a:ver2.0:extended:urn:www.ubl-italia.org:spec:ordine:ver2.1</CustomizationID>
<ID>ORD-001</ID>
<IssueDate>2016-10-01</IssueDate>
<OrderTypeCode listID="UNCL1001">221</OrderTypeCode>
<ns3:ValidityPeriod>
<EndDate>2024-10-19</EndDate>
</ns3:ValidityPeriod>
<ns3:BuyerCustomerParty>
<ns3:Party>
<EndpointID schemeID="IT:IPA">ITAK12MH</EndpointID>
<ns3:PartyIdentification>
<ID schemeID="IT:VAT">01567570254</ID>
</ns3:PartyIdentification>
<ns3:PartyName>
<Name>A Custom Name</Name>
</ns3:PartyName>
</ns3:Party>
</ns3:BuyerCustomerParty>
</ns10:Order>
Those files must be considered the same and so both valid.
A third example can be a file similar to the second where the namespaces are the same but their prefixes are different. Obviously the important thing is that the prefix used to match the namespace belongs to that particular tag.
I have no way of knowing in advance what will be the prefixes associated with namespaces.
<aaa:Order xmlns="urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2" xmlns:aaa="urn:oasis:names:specification:ubl:schema:xsd:Order-2" xmlns:bbb="urn:oasis:names:specification:ubl:schema:xsd:CommonAggregateComponents-2">
<UBLVersionID>2.1</UBLVersionID>
<CustomizationID>urn:www.cenbii.eu:transaction:biitrns001:ver2.0:extended:urn:www.peppol.eu:bis:peppol3a:ver2.0:extended:urn:www.ubl-italia.org:spec:ordine:ver2.1</CustomizationID>
<ID>ORD-001</ID>
<IssueDate>2016-10-01</IssueDate>
<OrderTypeCode listID="UNCL1001">221</OrderTypeCode>
<bbb:ValidityPeriod>
<EndDate>2024-10-19</EndDate>
</bbb:ValidityPeriod>
<bbb:BuyerCustomerParty>
<bbb:Party>
<EndpointID schemeID="IT:IPA">ITAK12MH</EndpointID>
<bbb:PartyIdentification>
<ID schemeID="IT:VAT">01567570254</ID>
</bbb:PartyIdentification>
<bbb:PartyName>
<Name>A Custom Name</Name>
</bbb:PartyName>
</bbb:Party>
</bbb:BuyerCustomerParty>
</aaa:Order>
This last file must be considered valid as the others.
As you can see, the association between the tags and their namespaces are always the same. The only things that are changed are the prefixes.
My actual code uses XDocument and XElement classes to read the XML but it can be the way because I need to know the exact prefix for each tag and since they can vary, it works only with the first XML file sample.
XDocument doc;
XmlNamespaceManager manager;
using (XmlReader reader = XmlReader.Create(stream))
{
doc = XDocument.Load(reader);
// Retrieving namespaces of XML file
XPathNavigator navigator = doc.CreateNavigator();
navigator.MoveToFollowing(XPathNodeType.Element);
IDictionary<string, string> namespaces = navigator.GetNamespacesInScope(XmlNamespaceScope.All);
// Add namespaces to an XmlNamespaceManager to read nodes
manager = new XmlNamespaceManager(reader.NameTable);
foreach (KeyValuePair<string, string> ns in namespaces)
{
manager.AddNamespace(ns.Key, ns.Value);
}
}
XElement currentNode;
currentNode = doc.Root.XPathSelectElement("cbc:ID", manager);
if (currentNode != null)
item.DespatchAdviceId = currentNode.Value;
currentNode = doc.Root.XPathSelectElement("cbc:IssueDate", manager);
if (currentNode != null)
{
DateTime dataEmissione;
if (DateTime.TryParseExact(currentNode.Value, validDateFormats, CultureInfo.InvariantCulture, DateTimeStyles.None, out dataEmissione))
item.OrderIssueDate = dataEmissione;
}
currentNode = doc.Root.XPathSelectElement("cac:BuyerCustomerParty/cac:Party/cac:PartyIdentification/cbc:ID", manager);
if (currentNode != null)
{
item.BuyerPartyId = currentNode.Value;
if (currentNode.Attribute("schemeID") != null)
item.BuyerPartySchemeId = currentNode.Attribute("schemeID").Value;
}
// ... and so on...
How can I read the XMLs without having to specify the namespace prefixes?
Should I use another .NET library or maybe a 3rd party one?

Using LocalName, you can linq it without adding the namespace.
//this is for <cbc:ID>ORD-001</cbc:ID>
var element = doc.Root.Elements().Where(x => x.Name.LocalName == "ID").FirstOrDefault();
If you want to go in the nested elements
var element = doc.Root.Elements().Where(x => x.Name.LocalName == "ValidityPeriod").
Elements().Where(x=> x.Name.LocalName == "EndDate").FirstOrDefault();

I need to know the exact prefix for each tag.
No, you don't. The prefixes are entirely irrelevant to qualified name of an element or attribute. If you want to go the XPath route, then don't read the namespaces and prefixes from the document to create your namespace manager, specify them yourself so you know what they are. Then use those in your query. For example, this will work with any of your XML documents:
var manager = new XmlNamespaceManager(new NameTable());
manager.AddNamespace("cbc",
"urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2");
var id = doc.Root.XPathSelectElement("cbc:ID", manager);
What I would encourage, though, is that you ditch XPath. LINQ to XML is so much nicer. And another quick hint, there is an overload of XDocument.Load that accepts a stream. There's no need to create the XmlReader. So:
XNamespace order = "urn:oasis:names:specification:ubl:schema:xsd:Order-2";
XNamespace cbc = "urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2";
XNamespace cac = "urn:oasis:names:specification:ubl:schema:xsd:CommonAggregateComponents-2";
var doc = XDocument.Load(stream);
var id = (string) doc.Elements(order + "Order")
.Elements(cbc + "ID")
.Single();
var issueDate = (DateTime) doc.Elements(order + "Order")
.Elements(cbc + "IssueDate")
.Single();
var buyerPartySchemeId = (string) doc.Descendants(cac + "BuyerCustomerParty")
.Descendants(cbc + "ID")
.Attributes("schemeID")
.Single();

How add,edit and delete node by line in xml

I have string XML. I loaded to XmlDocument. How can I add, edit and delete by simplest method by line, because I know only line which I should edit. It's better work wih XML like with string, or better work with XmlDocuments?
using System;
using System.Xml;
namespace testXMl
{
class Program
{
static void Main(string[] args)
{
string xml="<?xml version=\"1.0\"?>\r\n<application>\r\n<features>\r\n<test key=\"some_key\">\r\n</features>\r\n</application>";
XmlDocument xm = new XmlDocument();
xm.LoadXml(xml);
//Edit third line
//xm[3].EditName(featuresNew);
//xml->"<?xml version=\"1.0\"?>\r\n<application>\r\n<featuresNew>\r\n<test key=\"some_key\">\r\n</featuresNew>\r\n</application>"
//Add fourth line the Node
//xm[4].AddNode("FeatureNext");
//xml->"<?xml version=\"1.0\"?>\r\n<application>\r\n<FeatureNext>\r\n<FeatureNext>\r\n</features2>\r\n<test key=\"some_key\">\r\n</features>\r\n</application>"
//Delete sixth line
//xm[6].DeleteNode;
//xml->"<?xml version=\"1.0\"?>\r\n<application>\r\n<FeatureNext>\r\n<FeatureNext>\r\n</features2>\r\n</features>\r\n</application>"
}
}
}
Thanks, in advance.

You should always work with XDocument/XmlDocument objects. A key knowledge is the XPath query language.
This a quick XML crash course. Run with debugger and inspect the XML variable as you move on.
var xml = new XmlDocument();
xml.LoadXml(#"<?xml version='1.0'?>
<application>
<features>
<test key='some_key' />
</features>
</application>");
// Select an element to work with; I prefer to work with XmlElement instead of XmlNode
var test = (XmlElement) xml.SelectSingleNode("//test");
test.InnerText = "another";
test.SetAttribute("sample", "value");
var attr = test.GetAttribute("xyz"); // Works, even if that attribute doesn't exists
// Create a new element: you'll need to point where you should add a child element
var newElement = xml.CreateElement("newElement");
xml.SelectSingleNode("/application/features").AppendChild(newElement);
// You can also select elements by its position;
// in this example, take the second element inside "features" regardless its name
var delete = xml.SelectSingleNode("/application/features/*[2]");
// Trick part: if you found the element, navigate to its parent and remove the child
if (delete != null)
delete.ParentNode.RemoveChild(delete);

Extracting XML Child Elements Where the Parents are in a Defaulted Namespace

I have the below XML and I've been trying to extract the FirstName, LastName and OtherName for a while now I'm running into all sort of problems.
<OmdCds xmlns="cds"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:cdsd="cds_dt"
xsi:schemaLocation="cds ontariomd_cds.xsd">
<PatientRecord>
<Demographics>
<Names>
<cdsd:LegalName namePurpose="L">
<cdsd:FirstName>
<cdsd:Part>SARAH</cdsd:Part>
<cdsd:PartType>GIV</cdsd:PartType>
<cdsd:PartQualifier>BR</cdsd:PartQualifier>
</cdsd:FirstName>
<cdsd:LastName>
<cdsd:Part>GOMEZ</cdsd:Part>
<cdsd:PartType>FAMC</cdsd:PartType>
<cdsd:PartQualifier>BR</cdsd:PartQualifier>
</cdsd:LastName>
<cdsd:OtherName>
<cdsd:Part>GABRIELA</cdsd:Part>
<cdsd:PartType>GIV</cdsd:PartType>
<cdsd:PartQualifier>BR</PartQualifier>
I currently trying to extract with the below c# code but still can't extract the above data. I'm getting a nullreferenceexception.
XmlDocument doc = new XmlDocument();
doc.Load(folder + "\\" + o.ToString());
XmlNamespaceManager namespaceManager = new XmlNamespaceManager(doc.NameTable);
namespaceManager.AddNamespace("cdsd", "http://www.w3.org/2001/XMLSchema-instance");
XmlNode firstName = doc.DocumentElement.SelectSingleNode("/PatientRecord/Demographics/Names/cdsd:LegalName/cdsd:FirstName/cdsd:Part", namespaceManager);
string fName = firstName.InnerText;
MessageBox.Show(fName);
I can see in the local watch item under doc.DocumentElement, all the InnerXML and InnerText. The InnerXML look something like this...
<PatientRecord xmlns=\"cds\"><Demographics><Names><cdsd:LegalName namePurpose=\"L\" xmlns:cdsd=\"cds_dt\"><cdsd:FirstName><cdsd:Part>SARAH</cdsd:Part><cdsd:PartType>GIV</cdsd:PartType><cdsd:PartQualifier>BR</cdsd:PartQualifier></cdsd:FirstName>

You have 3 namespace definitions in the document:
cds - as a default namespace
http://www.w3.org/2001/XMLSchema-instance- with the xsi prefix
cds_dt - with the cdsd prefix
I am wondering that you don't get an error message, because cds and cds_dt are no URIs and namspaces need to be URIs.
If you try to understand an element name you need to replaces the prefix with the actual namespace.
<PatientRecord> reads as {cds}:PatientRecord
<cdsd:LegalName> reads as {cds_dt}:LegalName
Now in XPath 1.0 the same happens with registered namespaces. But XPath does not have a default namespace. So elements without one are not expanded with a default namespace.
You need to register namespace prefixes on the namespace manager. The prefix does not need to be the same as in the document.
namespaceManager.AddNamespace("cdsd", "cds_dt");
namespaceManager.AddNamespace("cds", "cds");
Now you can use the registered namespaces in XPath:
doc.DocumentElement.SelectSingleNode(
"cds:PatientRecord/cds:Demographics/cds:Names/cdsd:LegalName/cdsd:FirstName/cdsd:Part",
namespaceManager
);
If the first character of an XPath expression is a slash the expression is relative to the document, otherwise to the current context node. You call SelectSingleNode() on the doc.DocumentElement - the OmdCds element node. PatientRecord is a child node, so you can start with it or use . for the current context node.

PatientRecord, Demographics and Names are in the cds namespace. This is because of the default namespace declaration on the OmdCds element (xmlns="cds"). The others are in the cdsd namespace, not xsi. You'll have to add them and use them in the XPATH:
namespaceManager.AddNamespace("cdsd", "cdsd");
namespaceManager.AddNamespace("cds", "cds");
XmlNode firstName = doc.DocumentElement.SelectSingleNode(
"/cds:PatientRecord/cds:Demographics/cds:Names/cdsd:LegalName/cdsd:FirstName/cdsd:Part",
namespaceManager);
BTW, you're getting a NullReferenceException because you're making the false assumption that your query will always return a node. You are now seeing what happens when it does not return a node. Always check for null whenever it's possible that a query returns no value.

Instead XmlDocument class you can use Linq to XML, is easy. You need using the System.Xml.Linq namspace, for example:
XDocument xdoc = XDocument.Load("path");
IEnumerable<XElement> nodes = (from p in xdoc.Descendants()
where p.Name.LocalName == "FirstName"
select p).Elements();
foreach (XElement nodeFirstName in nodes)
{
foreach (XElement parts in nodeFirstName.Elements())
{
string strExtracted = parts.Name.LocalName + " " + parts.Value;
}
}
The LocalName property is used beacuse elements have a prefix "cdsd"

creating elements with namespace prefix based on multipart xml root declaration

If I do something like this:
System.Xml.XmlDocument xmlDoc = new System.Xml.XmlDocument();
XmlElement e = xmlDoc.CreateElement("ShipmentReceiptNotification");
e.SetAttribute("xmlns", "urn:rosettanet:specification:interchange:ShipmentReceiptNotification:xsd:schema:02.02");
e.SetAttribute("xmlns:ssdh", "urn:rosettanet:specification:domain:Procurement:AccountClassification:xsd:codelist:01.03");
XmlNode ShipmentReceiptNotification0Node = e;
ShipmentReceiptNotification0Node.InnerText = String.Empty;
xmlDoc.AppendChild(ShipmentReceiptNotification0Node);
XmlNode DocumentHeader1Node = xmlDoc.CreateElement("ssdh:DocumentHeader");
ShipmentReceiptNotification0Node.AppendChild(DocumentHeader1Node);
It will result in the prefix of the second node ssdh not to display, only DocumentHeader is displayed. How could I fix this?

You need to create it like this:
XmlNode DocumentHeader1Node = xmlDoc.CreateElement("ssdh", "DocumentHeader", "urn:rosettanet:specification:domain:Procurement:AccountClassification:xsd:codelist:01.03");
The point is XmlDocument needs to know which namespace prefix (first argument) corresponds which namespace URI (third argument). A little bit counter-intuitive, but this is the way it works.
Also note that the line ShipmentReceiptNotification0Node.InnerText = String.Empty; is useless; it's safe to omit it, the element is empty by default.

C# Xml Value always getting null

I have the following Xml in my Resources.xmltest:
<?xml version="1.0" encoding="utf-8" ?>
<Response xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns="http://DFISofft.com/SmartPayments/">
<Result>0</Result>
<Message>Pending</Message>
<PNRef>222131</PNRef>
<ExtData>InvNum=123</ExtData>
</Response>
I've tried several ways to get the values, Result,Message,PNRef,ExtData, out of it and I've had no luck. I always get a null value for the NodePath so it never goes into the loop:
var XmlDoc = new XmlDocument();
XmlDoc.LoadXml(Resources.xmltest);
XmlElement NodePath = (XmlElement) XmlDoc.SelectSingleNode("/Response");
while (NodePath != null)
{
foreach (XmlNode Xml_Node in NodePath)
{
Console.WriteLine(Xml_Node.Name + " " + Xml_Node.InnerText);
}
}
I've tried this:
XmlNode node3 = XmlDoc.SelectSingleNode("PNRef");
Console.WriteLine(node3.Value);
Console.WriteLine(XmlDoc.InnerXml);
var tst = XmlDoc.GetElementsByTagName("PNRef");
Console.WriteLine(tst);
And this:
NodePath = (XmlElement) XmlDoc.SelectSingleNode("/Response");
if (NodePath != null)
{
foreach (XmlNode node in NodePath)
{
Console.WriteLine("NodeName: " + Xml_NodeX.Name);
Console.WriteLine("NodeValue: " + node.InnerText);
}
}
Apparently, I'm not getting the xml read/write. I've done it with DataSets but they do all the work for you.
Can someone point me in the right direction? I've been at this for longer than I should have been already.
Thank you!

Your XML has a XML namespace and you're not paying any attention to it:
<Response xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns="http://DFISofft.com/SmartPayments/">
******************************************
When selecting from this XML, you need to use that XML namespace!
You're not taking into account the XML namespace (xmlns="http://nts-de-osm1-pxc/webservices/") on the document!
Try this:
var XmlDoc = new XmlDocument();
// setup the XML namespace manager
XmlNamespaceManager mgr = new XmlNamespaceManager(XmlDoc.NameTable);
// add the relevant namespaces to the XML namespace manager
mgr.AddNamespace("ns", "http://DFISofft.com/SmartPayments/");
XmlDoc.LoadXml(Resources.xmltest);
// **USE** the XML anemspace in your XPath !!
XmlElement NodePath = (XmlElement) XmlDoc.SelectSingleNode("/ns:Response");
while (NodePath != null)
{
foreach (XmlNode Xml_Node in NodePath)
{
Console.WriteLine(Xml_Node.Name + " " + Xml_Node.InnerText);
}
}

The problem is your XPath query, which doesn't specify a namespace - despite the fact that your document only has a Response element in the "http://DFISofft.com/SmartPayments/" namespace. Ditto the PNRef elements.
Personally I'd use LINQ to XML if I actually wanted to use namespaces if at all possible. For example:
XNamespace ns = "http://DFISofft.com/SmartPayments/";
XDocument doc = XDocument.Load(filename);
foreach (var element in doc.Descendants(ns + "PNRef"))
{
// Use element here
}
As you can see, LINQ to XML makes it really easy to use namespaces - but of course it requires .NET 3.5 or higher. If I had to use .NET 2.0, I'd either use XmlNamespaceManager or iterate manually and check local names instead of using XPath.

That is because the node isn't called response; you need to take the namespace into account:
var XmlDoc = new XmlDocument();
var nsmgr = new XmlNamespaceManager(XmlDoc.NameTable);
nsmgr.AddNamespace("x", "http://DFISofft.com/SmartPayments/");
XmlDoc.LoadXml(yourXml);
XmlElement NodePath = (XmlElement)XmlDoc.SelectSingleNode("/x:Response", nsmgr);

For future reference...
Bubba Soft
This site has a great free tool for building XPath Expressions (XPath Builder).

It's because you are using the overload of SelectSingleNode that assumes an empty namespace. Since you have a default namespace you will need to use the version that takes an XmlNamespaceManager. See this article for more info.
from the docs:
If the XPath expression does not include a prefix, it is assumed that the namespace URI is the empty namespace. If your XML includes a default namespace, you must still add a prefix and namespace URI to the XmlNamespaceManager; otherwise, you will not get a node selected. For more information, see Select Nodes Using XPath Navigation.