XPathExpression.ReturnType Property
Definition
Important
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When overridden in a derived class, gets the result type of the XPath expression.
public:
abstract property System::Xml::XPath::XPathResultType ReturnType { System::Xml::XPath::XPathResultType get(); };
public abstract System.Xml.XPath.XPathResultType ReturnType { get; }
member this.ReturnType : System.Xml.XPath.XPathResultType
Public MustOverride ReadOnly Property ReturnType As XPathResultType
Property Value
An XPathResultType value representing the result type of the XPath expression.
Examples
The following example shows how to use the XPath return type to determine how to process the XPath expression.
public ref class Sample
{
public:
static void Evaluate( XPathExpression^ expr, XPathNavigator^ nav )
{
XPathNodeIterator^ i = nav->Select(expr);
switch ( expr->ReturnType )
{
case XPathResultType::Number:
Console::WriteLine( nav->Evaluate( expr ) );
break;
case XPathResultType::NodeSet:
while ( i->MoveNext() )
Console::WriteLine( i->Current );
break;
case XPathResultType::Boolean:
if ( *safe_cast<bool^>(nav->Evaluate( expr )) )
Console::WriteLine( "True!" );
break;
case XPathResultType::String:
Console::WriteLine( nav->Evaluate( expr ) );
break;
}
}
};
int main()
{
XPathDocument^ doc = gcnew XPathDocument( "contosoBooks.xml" );
XPathNavigator^ nav = doc->CreateNavigator();
XPathExpression^ expr1 = nav->Compile( ".//price/text()*10" ); // Returns a number.
XPathExpression^ expr2 = nav->Compile( "bookstore/book/price" ); // Returns a nodeset.
Sample^ MySample = gcnew Sample;
MySample->Evaluate( expr1, nav );
MySample->Evaluate( expr2, nav );
}
using System;
using System.Xml;
using System.Xml.XPath;
public class XPathExpressionExample
{
public static void Main()
{
XPathDocument document = new XPathDocument("contosoBooks.xml");
XPathNavigator navigator = document.CreateNavigator();
XPathExpression expression1 = XPathExpression.Compile(".//bk:price/text()*10"); // Returns a number.
XPathExpression expression2 = XPathExpression.Compile("bk:bookstore/bk:book/bk:price"); // Returns a nodeset.
XmlNamespaceManager manager = new XmlNamespaceManager(navigator.NameTable);
manager.AddNamespace("bk", "http://www.contoso.com/books");
expression1.SetContext(manager);
expression2.SetContext(manager);
Evaluate(expression1, navigator);
Evaluate(expression2, navigator);
}
public static void Evaluate(XPathExpression expression, XPathNavigator navigator)
{
switch (expression.ReturnType)
{
case XPathResultType.Number:
Console.WriteLine(navigator.Evaluate(expression));
break;
case XPathResultType.NodeSet:
XPathNodeIterator nodes = navigator.Select(expression);
while (nodes.MoveNext())
{
Console.WriteLine(nodes.Current.ToString());
}
break;
case XPathResultType.Boolean:
if ((bool)navigator.Evaluate(expression))
Console.WriteLine("True!");
break;
case XPathResultType.String:
Console.WriteLine(navigator.Evaluate(expression));
break;
}
}
}
Imports System.Xml
Imports System.Xml.XPath
Public Class XPathExpressionExample
Public Shared Sub Main()
Dim document As XPathDocument = New XPathDocument("contosoBooks.xml")
Dim navigator As XPathNavigator = document.CreateNavigator()
Dim expression1 As XPathExpression = XPathExpression.Compile(".//bk:price/text()*10") ' Returns a number.
Dim expression2 As XPathExpression = XPathExpression.Compile("bk:bookstore/bk:book/bk:price") ' Returns a nodeset.
Dim manager As XmlNamespaceManager = New XmlNamespaceManager(navigator.NameTable)
manager.AddNamespace("bk", "http://www.contoso.com/books")
expression1.SetContext(manager)
expression2.SetContext(manager)
Evaluate(expression1, navigator)
Evaluate(expression2, navigator)
End Sub
Public Shared Sub Evaluate(ByVal expression As XPathExpression, ByVal navigator As XPathNavigator)
Select Case expression.ReturnType
Case XPathResultType.Number
Console.WriteLine(navigator.Evaluate(expression))
Exit Sub
Case XPathResultType.NodeSet
Dim nodes As XPathNodeIterator = navigator.Select(expression)
While nodes.MoveNext()
Console.WriteLine(nodes.Current.ToString())
End While
Case XPathResultType.Boolean
If CType(navigator.Evaluate(expression), Boolean) Then
Console.WriteLine("True!")
End If
Case XPathResultType.String
Console.WriteLine(navigator.Evaluate(expression))
End Select
End Sub
End Class
The example takes the contosoBooks.xml
file as input.
<?xml version="1.0" encoding="utf-8" ?>
<bookstore xmlns="http://www.contoso.com/books">
<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>
Applies to
See also
Dolgozzon együtt velünk a GitHubon
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