XPathNavigator.NamespaceURI Property  
Definition
Important
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When overridden in a derived class, gets the namespace URI of the current node.
public:
 abstract property System::String ^ NamespaceURI { System::String ^ get(); };public abstract string NamespaceURI { get; }member this.NamespaceURI : stringPublic MustOverride ReadOnly Property NamespaceURI As StringProperty Value
A String that contains the namespace URI of the current node, or Empty if the current node has no namespace URI.
Examples
The following example iterates over the node tree recursively, and displays information about Element and Text nodes.
static void XPathNavigatorMethods_MoveToNext()
{
    XPathDocument document = new XPathDocument("books.xml");
    XPathNavigator navigator = document.CreateNavigator();
    XPathNodeIterator nodeset = navigator.Select("descendant::book[author/last-name='Melville']");
    while (nodeset.MoveNext())
    {
        // Clone iterator here when working with it.
        RecursiveWalk(nodeset.Current.Clone());
    }
}
public static void RecursiveWalk(XPathNavigator navigator)
{
    switch (navigator.NodeType)
    {
        case XPathNodeType.Element:
            if (string.IsNullOrEmpty(navigator.Prefix))
                Console.WriteLine("<{0}>", navigator.LocalName);
            else
                Console.Write("<{0}:{1}>", navigator.Prefix, navigator.LocalName);
            Console.WriteLine("\t" + navigator.NamespaceURI);
            break;
        case XPathNodeType.Text:
            Console.WriteLine("\t" + navigator.Value);
            break;
    }
    if (navigator.MoveToFirstChild())
    {
        do
        {
            RecursiveWalk(navigator);
        } while (navigator.MoveToNext());
        navigator.MoveToParent();
        if (navigator.NodeType == XPathNodeType.Element)
            Console.WriteLine("</{0}>", navigator.Name);
    }
    else
    {
        if (navigator.NodeType == XPathNodeType.Element)
        {
            Console.WriteLine("</{0}>", navigator.Name);
        }
    }
}
Shared Sub XPathNavigatorMethods_MoveToNext()
    Dim document As XPathDocument = New XPathDocument("books.xml")
    Dim navigator As XPathNavigator = document.CreateNavigator()
    Dim nodeset As XPathNodeIterator = navigator.Select("descendant::book[author/last-name='Melville']")
    While nodeset.MoveNext()
        ' Clone iterator here when working with it.
        RecursiveWalk(nodeset.Current.Clone())
    End While
End Sub
Shared Sub RecursiveWalk(ByVal navigator As XPathNavigator)
    Select Case navigator.NodeType
        Case XPathNodeType.Element
            If navigator.Prefix = String.Empty Then
                Console.WriteLine("<{0}>", navigator.LocalName)
            Else
                Console.Write("<{0}:{1}>", navigator.Prefix, navigator.LocalName)
                Console.WriteLine(vbTab + navigator.NamespaceURI)
            End If
        Case XPathNodeType.Text
            Console.WriteLine(vbTab + navigator.Value)
    End Select
    If navigator.MoveToFirstChild() Then
        Do
            RecursiveWalk(navigator)
        Loop While (navigator.MoveToNext())
        navigator.MoveToParent()
        If (navigator.NodeType = XPathNodeType.Element) Then
            Console.WriteLine("</{0}>", navigator.Name)
        End If
    Else
        If navigator.NodeType = XPathNodeType.Element Then
            Console.WriteLine("</{0}>", navigator.Name)
        End If
    End If
End Sub
The example takes the books.xml file as an input.
<?xml version="1.0" encoding="utf-8" ?>
<bookstore>
    <book genre="autobiography" publicationdate="1981-03-22" ISBN="1-861003-11-0">
        <title>The Autobiography of Benjamin Franklin</title>
        <author>
            <first-name>Benjamin</first-name>
            <last-name>Franklin</last-name>
        </author>
        <price>8.99</price>
    </book>
    <book genre="novel" publicationdate="1967-11-17" ISBN="0-201-63361-2">
        <title>The Confidence Man</title>
        <author>
            <first-name>Herman</first-name>
            <last-name>Melville</last-name>
        </author>
        <price>11.99</price>
    </book>
    <book genre="philosophy" publicationdate="1991-02-15" ISBN="1-861001-57-6">
        <title>The Gorgias</title>
        <author>
            <name>Plato</name>
        </author>
        <price>9.99</price>
    </book>
</bookstore>
Remarks
The namespace URI returned depends on the XPathNodeType of the current node.
The NamespaceURI property returns urn:samples for the node <bk:book xmlns:bk='urn:samples'>.
Only Element and AttributeXPathNodeType nodes can have a namespace URI.