XPathNavigator.NavigatorComparer Property

Definition

Namespace:

System.Xml.XPath

Assembly:

System.Xml.ReaderWriter.dll

Source:

XPathNavigator.cs

Gets an IEqualityComparer used for equality comparison of XPathNavigator objects.

public:
 static property System::Collections::IEqualityComparer ^ NavigatorComparer { System::Collections::IEqualityComparer ^ get(); };

public static System.Collections.IEqualityComparer NavigatorComparer { get; }

static member NavigatorComparer : System.Collections.IEqualityComparer

Public Shared ReadOnly Property NavigatorComparer As IEqualityComparer

Property Value

IEqualityComparer

An IEqualityComparer used for equality comparison of XPathNavigator objects.

Examples

The following example illustrates the use of the NavigatorComparer property.

XPathDocument^ document = gcnew XPathDocument("books.xml");
XPathNavigator^ navigator = document->CreateNavigator();
Hashtable^ table = gcnew Hashtable(XPathNavigator::NavigatorComparer);

// Add nodes to the Hashtable.
for each (XPathNavigator^ navigator2 in navigator->Select("//book"))
{
    Object^ value = navigator2->Evaluate("string(./title)");
    table->Add(navigator2->Clone(), value);
    Console::WriteLine("Added book with title {0}", value);
}

Console::WriteLine(table->Count);
Console::WriteLine("Does the Hashtable have the book \"The Confidence Man\"?");
Console::WriteLine(table->Contains(navigator->SelectSingleNode("//book[title='The Confidence Man']")));

XPathDocument document = new XPathDocument("books.xml");
XPathNavigator navigator = document.CreateNavigator();
Hashtable table = new Hashtable(XPathNavigator.NavigatorComparer);

// Add nodes to the Hashtable.
foreach (XPathNavigator navigator2 in navigator.Select("//book"))
{
    object value = navigator2.Evaluate("string(./title)");
    table.Add(navigator2.Clone(), value);
    Console.WriteLine("Added book with title {0}", value);
}

Console.WriteLine(table.Count);
Console.WriteLine("Does the Hashtable have the book \"The Confidence Man\"?");
Console.WriteLine(table.Contains(navigator.SelectSingleNode("//book[title='The Confidence Man']")));

Dim document As XPathDocument = New XPathDocument("books.xml")
Dim navigator As XPathNavigator = document.CreateNavigator()
Dim table As Hashtable = New Hashtable(XPathNavigator.NavigatorComparer)

' Add nodes to the Hashtable.
For Each navigator2 As XPathNavigator In navigator.Select("//book")
    Dim value As Object = navigator2.Evaluate("string(./title)")
    table.Add(navigator2.Clone(), value)
    Console.WriteLine("Added book with title {0}", value)
Next

Console.WriteLine(table.Count)
Console.WriteLine("Does the Hashtable have the book 'The Confidence Man'?")
Console.WriteLine(table.Contains(navigator.SelectSingleNode("//book[title='The Confidence Man']")))

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 NavigatorComparer property allows XPathNavigator objects to be compared on the basis of position rather than reference to the object. The ComparePosition and Equals methods implemented by this class are based on the position of the XPathNavigator objects passed as parameters. The GetHashCode method implemented by this class uses the properties of the node such as its local name and namespace URI to create a hash code for the node.