Read an XML node in namespace using Linq - vb.net

Question

How do I work out what the namespace declaration is for the Extension node?
I want to return all of the child nodes under: GPO->User->ExtensionData->Extension
<?xml version="1.0" encoding="utf-16"?>
<GPO xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns="http://www.microsoft.com/GroupPolicy/Settings">
<User>
<VersionDirectory>4</VersionDirectory>
<VersionSysvol>4</VersionSysvol>
<Enabled>true</Enabled>
<ExtensionData>
<Extension xmlns:q1="http://www.microsoft.com/GroupPolicy/Settings/Scripts" xsi:type="q1:Scripts">
<q1:Script>
<q1:Command>Logon.cmd</q1:Command>
<q1:Type>Logon</q1:Type>
<q1:Order>0</q1:Order>
<q1:RunOrder>PSNotConfigured</q1:RunOrder>
</q1:Script>
</Extension>
<Name>Scripts</Name>
</ExtensionData>
</User>
<LinksTo>
<SOMName>an interesting data value</SOMName>
<SOMPath>some data value</SOMPath>
<Enabled>true</Enabled>
<NoOverride>false</NoOverride>
</LinksTo>
</GPO>
This is my attempt:
Dim NS As XNamespace = "http://www.microsoft.com/GroupPolicy/Settings/Scripts"
Dim UserPolCount = XDoc.Descendants(NS + "Extension").First()
I get the following error: Sequence contains no elements
Also, the XML sample I have provided is only a small snippet, the ExtensionData->Extension nodes can be nested in different areas, so I was hoping to find the way of specifying the full path.
Thanks

Answer 1

The Extension Element is still under the root namespace of:
http://www.microsoft.com/GroupPolicy/Settings
Elements under Extension are under the Scripts namespace:
http://www.microsoft.com/GroupPolicy/Settings/Scripts
So you need:
Dim NS As XNamespace = "http://www.microsoft.com/GroupPolicy/Settings/"
Dim NS1 As XNamespace = "http://www.microsoft.com/GroupPolicy/Settings/Scipts"
Dim UserPolCount = XDoc.Descendants(NS + "Extension").First()
Dim ScriptNode = UserPolCount.Elements(NS1 + "Script")
EDIT From the comments:
Dim extension =
XDoc
.Root
.Element(NS + "User")
.Element(NS + "ExtensionData")
.Element(NS + "Extension");

Answer 2

You are using the wrong namespace. You need to use http://www.microsoft.com/GroupPolicy/Settings as the namespace.
The reason is that only the children of Extension are in the Scripts namespace. You can easily see this: The children are all prefixed with q1, the Extension tag itself not. Therefore it is defined in the default namespace, defined by the attribute xmlns="http://www.microsoft.com/GroupPolicy/Settings" on the root tag GPO.