Selectsinglenode Returns Null When Tag Contains Xmlnamespace

SelectSingleNode returns null when tag contains xmlNamespace

You should use an XmlNamespaceManager in your call to SelectSingleNode():

XmlNamespaceManager ns = new XmlNamespaceManager(xmldoc.NameTable);
ns.AddNamespace("msbld", "http://schemas.microsoft.com/developer/msbuild/2003");
XmlNode node = xmldoc.SelectSingleNode("//msbld:Compile", ns);

SelectSingleNode returns null even with namespace managing

Your XML has default namespace which descendant elements without prefix implicitly inherits from the ancestor. That implies, not only the root element but all elements mentioned in your XPath are in the same default namespace, hence need to be referenced by using the same prefix :

//CIP4NS:Command/CIP4NS:ResourceCmdParams/CIP4NS:InkZoneProfile/CIP4NS:InkZoneProfile/CIP4NS:InkZoneProfile/CIP4NS:InkZoneProfile

C# SelectSingleNode returns null

1. your XML path is wrong: g is not a child of sodipodi:namedview. They are siblings.
2. the XPath is malformed: remove the trailing ']' character
3. you have defined a default namespace by declaring xmlns="http://www.w3.org/2000/svg" (no alias/prefix) on the svg element, but you are not qualifying the child types of the declaring node using the default namespace. According to XML namespace rules, the default namespace is "inherited" to all child elements of the parent that defines the namespace (svg in this case). The default namespace of an element defines an implicit prefix, that implicitly applies to all child elements..

To be able to qualify your elements using the default namespace, you first must register it

xmlnsManager.AddNamespace("default", "http://www.w3.org/2000/svg");

where default is a random alias to map the default namespace.

After registering the default namespace, modify the XPath to qualify child types of svg using the alias.

The fixed XPath would look as followed:

XmlNode node = document.DocumentElement.SelectSingleNode("default:g/default:image", xmlnsManager);

Alternatively remove the default namespace declaration xmlns="http://www.w3.org/2000/svg" from the svg element.

C# Xml SelectSingleNode returns null

Just use XmlNamespaceManager

XmlNamespaceManager namespaces = new XmlNamespaceManager(xdoc.NameTable);
namespaces.AddNamespace("sp", "http://www.webserviceX.NET");
var nodes = xdoc.DocumentElement.SelectSingleNode("//sp:NewDataSet/sp:Table[1]/sp:Country", namespaces);

Xmldoc .selectsinglenode returns null

Don't forget to use Xml namespaces

XmlNamespaceManager nsMgr = new XmlNamespaceManager(xDoc.NameTable);
nsMgr.AddNamespace("x", "http://usop.ctadvantage.com/");
XmlNode targetNode = xDoc.SelectSingleNode("/x:SOPDetail/x:TargetInfo/x:DomesticJurisdiction", nsMgr);

SelectSingleNode returns a null value

The Powershell syntax for NameTable handling is pretty similar to C#. After loading the data, create a NamespaceManager based on the XML document.

To select elements, a dummy namespace prefix needs to be used, in this sample x is added and used in Xpath. Like so,

[xml]$xml = Get-Content MyXml.xml
$nsmgr = new-object Xml.XmlNamespaceManager($xml.NameTable)
$nsmgr.AddNameSpace("x", "http://microsoft.com/GroupPolicy/GPOOperations/MigrationTable")
$xml.MigrationTable.Mapping[1].SelectSingleNode("x:DestinationSameAsSource", $nsmgr)

Null return on XmlDocument.SelectSingleNode through valid xpath

You have introduced default namespace here :

xmlns="http://www.origostandards.com/schema/ce/v2.1/CEBondSingleContractDetailResponse" 

which causes message element and all of it's descendants without prefix to be recognized as in that default namespace (unless the descendant element has local default namespace). To access element in default namespace, simply register a prefix, for example d, and map it to the default namespace uri :

nsmgr.AddNamespace("d", "http://www.origostandards.com/schema/ce/v2.1/CEBondSingleContractDetailResponse");

Then use the newly registered prefix accordingly in the XPath expression :

XmlNode xnBody = xmlDoc.SelectSingleNode("//soapenv:Envelope/soapenv:Body", nsmgr);
XmlNode xnMessage = xnBody.SelectSingleNode("d:message", nsmgr);

SelectSingleNode always returns null?

You're missing the XML namespace defined by the <message> node in your SelectSingleNode call. Assuming oss is an XmlDocument instance, you need to do this:

XmlNamespaceManager nsMgr = new XmlNamespaceManager(oss.NameTable);
nsMgr.AddNamespace("ns", "http://www.mydomain.com/MyDataFeed");

XmlNode errorNode = oss.SelectSingleNode("/ns:message/ns:error", nsMgr);

Marc

Why is SelectSingleNode returning null?

I cannot replicate this using an XML file

<MT>
  <Events>
    <event id="1">
      <field name="blah" value="a_value" type="atype" />
     </event>
   </Events>
</MT>

And code

XmlDocument doc = new XmlDocument();
doc.Load(@"C:\test.xml");

XmlNode node = doc.SelectSingleNode("//event[@id='1']");

This returns a non-null node as expected.

Update

After adding a xmlns="example.org" to the <MT> element, I had to configure a namespace manager for the XPath and use the namespace for the event. Couldn't get the default namespace to work for some reason.

XmlDocument doc = new XmlDocument();
doc.Load(@"D:\test.xml");

XmlNamespaceManager manager = new XmlNamespaceManager(doc.NameTable);
manager.AddNamespace("e", "http://example.org");

XmlNode node = doc.SelectSingleNode("//e:event[@id='1']", manager);

One thing confused me when trying to get this to work. Why does XmlNamespaceManager need XmlNameTable from the document if not for finding out what namespaces it contains? As in, why do I need to define the NameTable and the namespace? I'd appreciate if someone who knows could drop a short comment.

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