Develop Reference

Adding child node inside a XML node using C#

Here is my given XML:-
<?xml version="1.0" encoding="utf-8"?>
<Processes>
<Process Name="Process1" Namespace="" Methodname="">
<Validations/>
<Transformations/>
<Routings/>
</Process>
</Processes>
I want to add new node Validation inside Validations and for that i have written the following code:-
XmlDocument originalXml = new XmlDocument();
originalXml.Load(#"C:\Users\Sid\Desktop\Process\Process1.xml");
XmlNode Validations = originalXml.SelectSingleNode("/Processes/Process[Name="Process1"]/Validations");
XmlNode Validation = originalXml.CreateNode(XmlNodeType.Element, "Validation",null);
Validation.InnerText = "This is my new Node";
Validations.AppendChild(Validation);
originalXml.Save(#"C:\Users\Sid\Desktop\Process\Process1.xml");
But, I am getting error in the line "Validations.AppendChild(validation)" as Object reference not set to an instance of an object. Please suggest some way to fix it.

You can do by this
XDocument doc = XDocument.Load(#"C:\Users\Sid\Desktop\Process\Process1.xml");
var a = doc.Descendants("Validations").FirstOrDefault();
a.Add(new XElement("Validation", "This is my new Node"));
doc.Save(#"C:\Users\Sid\Desktop\Process\Process1.xml");

Your SelectSingleNode() didn't match any element, hence the null-reference exception. Beside the conflicting double-quotes problem, you should use #attribute_name pattern to reference attribute using XPath. So the correct expression would be :
originalXml.SelectSingleNode("/Processes/Process[#Name='Process1']/Validations");

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"

Unable to use XmlDocument.SelectSingleNode on XML with Two Namespaces

I'm trying to parse the following XML:
<?xml version="1.0" encoding="utf-8"?>
<A2AAnf:MPPPPPP xsi:schemaLocation="urn:A2AAnf:xsd:$MPPPPPP.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:A2AAnf="urn:A2AAnf:xsd:$MPPPPPP">
<A2AAnf:Num>0</A2AAnf:Num>
<A2AAnf:FIT xmlns="urn:iso:std:iso:20022:xsd:003.001">
<Hdr>
<Inf>
<Mtd>TEST</Mtd>
</Inf>
</Hdr>
</A2AAnf:FIT>
I want to access the <Mtd> tag.
XMLQuire shows the path to be /A2AAnf:MPPPPPP/A2AAnf:FIT/dft:Hdr/dft:Inf/dft:Mtd, but when I'm trying to parse it using the following code:
XmlDocument xmldocument = new XmlDocument();
var xmlNameSpaceManager = new XmlNamespaceManager(xmldocument.NameTable);
xmlNameSpaceManager.AddNamespace("A2AAnf", "urn:A2AAnf:xsd:$MPPPPPP");
try
{
xmldocument.LoadXml(m_XML);
var node = xmldocument.SelectSingleNode("/A2AAnf:MPPPPPP/A2AAnf:FIT/dft:Hdr/dft:Inf/dft:Mtd", xmlNameSpaceManager);
}
I receive the following error:
namespace prefix 'dft' is not defined
And since I can't find "dft" in my XML, I also tried to remove the "dft" prefix and search for the same string without "dft". This time, nothing was returned.
What am I missing?

You have to add dft to your XmlNamespaceManager:
var xmlNameSpaceManager = new XmlNamespaceManager(xmldocument.NameTable);
xmlNameSpaceManager.AddNamespace("A2AAnf", "urn:A2AAnf:xsd:$MPPPPPP");
xmlNameSpaceManager.AddNamespace("dft", "urn:iso:std:iso:20022:xsd:003.001");
The prefixes you use in your XPath query have nothing to do with the prefixes used in the XML document. They are instead the prefixes you define in your XmlNamespaceManager.

How to modify DocumentElement.Prefix in XmlDocument

I have some sets of xml in which I have to add namespace prefix on nodes which doesn't have any prefix.
I have written a code which works for all nodes other than root element.
Please point me to the thing which I can do change the root element prefix as well.
private void ReplaceFile(string xmlfile)
{
XmlDocument doc = new XmlDocument();
doc.Load(xmlfile);
var a = doc.CreateAttribute("xmlns:mailxml12tm");
a.Value = "http://idealliance.org/Specs/mailxml12.0a/mailxml_tm";
doc.DocumentElement.Attributes.Append(a);
doc.DocumentElement.Prefix = "mailxml12tm";
//foreach (XmlNode item in doc.SelectNodes("//*").Cast<XmlNode>().Where(item => item.Prefix.Length == 0))
//{
// item.Prefix = "mailxml12tm";
//}
doc.Save(xmlfile);
}
The xml file:
<DeliveryApptCreateRequest
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
p3:ApptType="Pallet" p3:PickupOrDelivery="Delivery"
p3:ShipperApptRequestID="4490B0C07355" p3:SchedulerCRID="6498874"
xmlns:p3="http://idealliance.org/Specs/mailxml12.0a/mailxml_defs">
<SubmitterTrackingID xmlns="http://idealliance.org/Specs/mailxml12.0a/mailxml_tm">2CAD3FBC71B1E1517021</SubmitterTrackingID>
<DestinationEntry xmlns="http://idealliance.org/Specs/mailxml12.0a/mailxml_tm">No</DestinationEntry>
<OneTimeAppt xmlns="http://idealliance.org/Specs/mailxml12.0a/mailxml_tm">
<PreferredAppt>2012-07-01T09:00:00Z</PreferredAppt>
</OneTimeAppt>
</DeliveryApptCreateRequest>

Have you seen this answer: https://stackoverflow.com/a/2255337/219344
by Jeff Sternal?
If you've already declared your namespace in the root node, you just
need to change the SetAttribute call to use the unprefixed attribute
name. So if your root node defines a namespace like this:
<People xmlns:s='http://niem.gov/niem/structures/2.0'>
You can do this and the attribute will pick up the prefix you've
already established:
// no prefix on the first argument - it will be rendered as //
s:id='ID_Person_01' TempElement.SetAttribute("id",
"http://niem.gov/niem/structures/2.0", "ID_Person_01");
If you have not yet declared the namespace (and its prefix), the
three-string XmlDocument.CreateAttribute overload will do it for you:
// Adds the declaration to your root node var attribute =
xmlDocToRef.CreateAttribute("s", "id",
"http://niem.gov/niem/structures/2.0"); attribute.InnerText =
"ID_Person_01" TempElement.SetAttributeNode(attribute);

You can use the following:
XmlDocument doc = new XmlDocument();
doc.LoadXml("<test xmlns='123'/>");
XmlElement e = doc.DocumentElement;
e.Prefix = "a";
Console.WriteLine(doc.InnerXml);
Output:
<a:test xmlns="123" xmlns:a="123" />
Founded in msdn.
Edit:
Since it does not work with your main element you can use .Replace("<", "<Prefixe:")); on your root element as a String. It's not pretty but it does the job.

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.