XmlDsigXPathTransform Classe
Definizione
Importante
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Rappresenta la trasformazione XPath per una firma digitale come definita dalla specifica W3C.
public ref class XmlDsigXPathTransform : System::Security::Cryptography::Xml::Transformpublic class XmlDsigXPathTransform : System.Security.Cryptography.Xml.Transformtype XmlDsigXPathTransform = class
inherit TransformPublic Class XmlDsigXPathTransform
Inherits Transform- Ereditarietà
Esempio
In questa sezione sono riportati due esempi di codice. Il primo esempio di codice illustra come firmare e verificare un documento XML usando la XmlDsigXPathTransform classe con una firma della busta. In questo esempio viene firmato un documento XML e viene salvata la firma in un nuovo documento XML. Il secondo esempio di codice illustra come chiamare i membri della XmlDsigXPathTransform classe.
Esempio #1
//
// This example signs an XML file using an
// envelope signature. It then verifies the
// signed XML.
//
#using <System.Xml.dll>
#using <System.Security.dll>
#using <System.dll>
using namespace System;
using namespace System::Security::Cryptography;
using namespace System::Security::Cryptography::X509Certificates;
using namespace System::Security::Cryptography::Xml;
using namespace System::Text;
using namespace System::Xml;
// Create the XML that represents the transform.
static XmlDsigXPathTransform^ CreateXPathTransform( String^ XPathString )
{
// Create a new XMLDocument object.
XmlDocument^ doc = gcnew XmlDocument;
// Create a new XmlElement.
XmlElement^ xPathElem = doc->CreateElement( L"XPath" );
// Set the element text to the value
// of the XPath string.
xPathElem->InnerText = XPathString;
// Create a new XmlDsigXPathTransform object.
XmlDsigXPathTransform^ xForm = gcnew XmlDsigXPathTransform;
// Load the XPath XML from the element.
xForm->LoadInnerXml( xPathElem->SelectNodes( L"." ) );
// Return the XML that represents the transform.
return xForm;
}
// Sign an XML file and save the signature in a new file.
static void SignXmlFile( String^ FileName, String^ SignedFileName, RSA^ Key, String^ XPathString )
{
// Create a new XML document.
XmlDocument^ doc = gcnew XmlDocument;
// Format the document to ignore white spaces.
doc->PreserveWhitespace = false;
// Load the passed XML file using it's name.
doc->Load( gcnew XmlTextReader( FileName ) );
// Create a SignedXml object.
SignedXml^ signedXml = gcnew SignedXml( doc );
// Add the key to the SignedXml document.
signedXml->SigningKey = Key;
// Create a reference to be signed.
Reference^ reference = gcnew Reference;
reference->Uri = L"";
// Create an XmlDsigXPathTransform object using
// the helper method 'CreateXPathTransform' defined
// later in this sample.
XmlDsigXPathTransform^ XPathTransform = CreateXPathTransform( XPathString );
// Add the transform to the reference.
reference->AddTransform( XPathTransform );
// Add the reference to the SignedXml object.
signedXml->AddReference( reference );
// Add an RSAKeyValue KeyInfo (optional; helps recipient find key to validate).
KeyInfo^ keyInfo = gcnew KeyInfo;
keyInfo->AddClause( gcnew RSAKeyValue( dynamic_cast<RSA^>(Key) ) );
signedXml->KeyInfo = keyInfo;
// Compute the signature.
signedXml->ComputeSignature();
// Get the XML representation of the signature and save
// it to an XmlElement object.
XmlElement^ xmlDigitalSignature = signedXml->GetXml();
// Append the element to the XML document.
doc->DocumentElement->AppendChild( doc->ImportNode( xmlDigitalSignature, true ) );
// Save the signed XML document to a file specified
// using the passed string.
XmlTextWriter^ xmltw = gcnew XmlTextWriter( SignedFileName,gcnew UTF8Encoding( false ) );
doc->WriteTo( xmltw );
xmltw->Close();
}
// Verify the signature of an XML file and return the result.
static Boolean VerifyXmlFile( String^ Name )
{
// Create a new XML document.
XmlDocument^ xmlDocument = gcnew XmlDocument;
// Format using white spaces.
xmlDocument->PreserveWhitespace = true;
// Load the passed XML file into the document.
xmlDocument->Load( Name );
// Create a new SignedXml object and pass it
// the XML document class.
SignedXml^ signedXml = gcnew SignedXml( xmlDocument );
// Find the "Signature" node and create a new
// XmlNodeList object.
XmlNodeList^ nodeList = xmlDocument->GetElementsByTagName( L"Signature" );
// Load the signature node.
signedXml->LoadXml( dynamic_cast<XmlElement^>(nodeList->Item( 0 )) );
// Check the signature and return the result.
return signedXml->CheckSignature();
}
// Create example data to sign.
static void CreateSomeXml( String^ FileName )
{
// Create a new XmlDocument object.
XmlDocument^ document = gcnew XmlDocument;
// Create a new XmlNode object.
XmlNode^ node = document->CreateNode( XmlNodeType::Element, L"", L"MyXML", L"Don't_Sign" );
// Append the node to the document.
document->AppendChild( node );
// Create a new XmlNode object.
XmlNode^ subnode = document->CreateNode( XmlNodeType::Element, L"", L"TempElement", L"Sign" );
// Add some text to the node.
subnode->InnerText = L"Here is some data to sign.";
// Append the node to the document.
document->DocumentElement->AppendChild( subnode );
// Save the XML document to the file name specified.
XmlTextWriter^ xmltw = gcnew XmlTextWriter( FileName,gcnew UTF8Encoding( false ) );
document->WriteTo( xmltw );
xmltw->Close();
}
int main()
{
// Generate a signing key.
RSA^ Key = RSA::Create();
try
{
// Create an XML file to sign.
CreateSomeXml( L"Example.xml" );
Console::WriteLine( L"New XML file created." );
// Sign the XML that was just created and save it in a
// new file.
SignXmlFile( L"Example.xml", L"SignedExample.xml", Key, L"ancestor-or-self::TempElement" );
Console::WriteLine( L"XML file signed." );
// Verify the signature of the signed XML.
Console::WriteLine( L"Verifying signature..." );
bool result = VerifyXmlFile( L"SignedExample.xml" );
// Display the results of the signature verification to \
// the console.
if ( result )
{
Console::WriteLine( L"The XML signature is valid." );
}
else
{
Console::WriteLine( L"The XML signature is not valid." );
}
}
catch ( CryptographicException^ e )
{
Console::WriteLine( e->Message );
}
finally
{
Key->Clear();
}
return 1;
}
//
// This example signs an XML file using an
// envelope signature. It then verifies the
// signed XML.
//
using System;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using System.Security.Cryptography.Xml;
using System.Text;
using System.Xml;
public class SignVerifyEnvelope
{
public static void Main(String[] args)
{
// Generate a signing key.
RSA Key = RSA.Create();
try
{
// Create an XML file to sign.
CreateSomeXml("Example.xml");
Console.WriteLine("New XML file created.");
// Sign the XML that was just created and save it in a
// new file.
SignXmlFile("Example.xml", "SignedExample.xml", Key, "ancestor-or-self::TempElement");
Console.WriteLine("XML file signed.");
// Verify the signature of the signed XML.
Console.WriteLine("Verifying signature...");
bool result = VerifyXmlFile("SignedExample.xml");
// Display the results of the signature verification to \
// the console.
if (result)
{
Console.WriteLine("The XML signature is valid.");
}
else
{
Console.WriteLine("The XML signature is not valid.");
}
}
catch (CryptographicException e)
{
Console.WriteLine(e.Message);
}
finally
{
Key.Clear();
}
}
// Sign an XML file and save the signature in a new file.
public static void SignXmlFile(string FileName, string SignedFileName, RSA Key, string XPathString)
{
// Create a new XML document.
XmlDocument doc = new XmlDocument();
// Format the document to ignore white spaces.
doc.PreserveWhitespace = false;
// Load the passed XML file using it's name.
doc.Load(new XmlTextReader(FileName));
// Create a SignedXml object.
SignedXml signedXml = new SignedXml(doc);
// Add the key to the SignedXml document.
signedXml.SigningKey = Key;
// Create a reference to be signed.
Reference reference = new Reference();
reference.Uri = "";
// Create an XmlDsigXPathTransform object using
// the helper method 'CreateXPathTransform' defined
// later in this sample.
XmlDsigXPathTransform XPathTransform = CreateXPathTransform(XPathString);
// Add the transform to the reference.
reference.AddTransform(XPathTransform);
// Add the reference to the SignedXml object.
signedXml.AddReference(reference);
// Add an RSAKeyValue KeyInfo (optional; helps recipient find key to validate).
KeyInfo keyInfo = new KeyInfo();
keyInfo.AddClause(new RSAKeyValue((RSA)Key));
signedXml.KeyInfo = keyInfo;
// Compute the signature.
signedXml.ComputeSignature();
// Get the XML representation of the signature and save
// it to an XmlElement object.
XmlElement xmlDigitalSignature = signedXml.GetXml();
// Append the element to the XML document.
doc.DocumentElement.AppendChild(doc.ImportNode(xmlDigitalSignature, true));
// Save the signed XML document to a file specified
// using the passed string.
XmlTextWriter xmltw = new XmlTextWriter(SignedFileName, new UTF8Encoding(false));
doc.WriteTo(xmltw);
xmltw.Close();
}
// Verify the signature of an XML file and return the result.
public static Boolean VerifyXmlFile(String Name)
{
// Create a new XML document.
XmlDocument xmlDocument = new XmlDocument();
// Format using white spaces.
xmlDocument.PreserveWhitespace = true;
// Load the passed XML file into the document.
xmlDocument.Load(Name);
// Create a new SignedXml object and pass it
// the XML document class.
SignedXml signedXml = new SignedXml(xmlDocument);
// Find the "Signature" node and create a new
// XmlNodeList object.
XmlNodeList nodeList = xmlDocument.GetElementsByTagName("Signature");
// Load the signature node.
signedXml.LoadXml((XmlElement)nodeList[0]);
// Check the signature and return the result.
return signedXml.CheckSignature();
}
// Create the XML that represents the transform.
private static XmlDsigXPathTransform CreateXPathTransform(string XPathString)
{
// Create a new XMLDocument object.
XmlDocument doc = new XmlDocument();
// Create a new XmlElement.
XmlElement xPathElem = doc.CreateElement("XPath");
// Set the element text to the value
// of the XPath string.
xPathElem.InnerText = XPathString;
// Create a new XmlDsigXPathTransform object.
XmlDsigXPathTransform xForm = new XmlDsigXPathTransform();
// Load the XPath XML from the element.
xForm.LoadInnerXml(xPathElem.SelectNodes("."));
// Return the XML that represents the transform.
return xForm;
}
// Create example data to sign.
public static void CreateSomeXml(string FileName)
{
// Create a new XmlDocument object.
XmlDocument document = new XmlDocument();
// Create a new XmlNode object.
XmlNode node = document.CreateNode(XmlNodeType.Element, "", "MyXML", "Don't_Sign");
// Append the node to the document.
document.AppendChild(node);
// Create a new XmlNode object.
XmlNode subnode = document.CreateNode(XmlNodeType.Element, "", "TempElement", "Sign");
// Add some text to the node.
subnode.InnerText = "Here is some data to sign.";
// Append the node to the document.
document.DocumentElement.AppendChild(subnode);
// Save the XML document to the file name specified.
XmlTextWriter xmltw = new XmlTextWriter(FileName, new UTF8Encoding(false));
document.WriteTo(xmltw);
xmltw.Close();
}
}
'
' This example signs an XML file using an
' envelope signature. It then verifies the
' signed XML.
'
Imports System.Security.Cryptography
Imports System.Security.Cryptography.X509Certificates
Imports System.Security.Cryptography.Xml
Imports System.Text
Imports System.Xml
Module SignVerifyEnvelope
Sub Main(ByVal args() As String)
' Generate a signing key.
Dim Key As RSA = RSA.Create()
Try
' Create an XML file to sign.
CreateSomeXml("Example.xml")
Console.WriteLine("New XML file created.")
' Sign the XML that was just created and save it in a
' new file.
SignXmlFile("Example.xml", "SignedExample.xml", Key, "ancestor-or-self::TempElement")
Console.WriteLine("XML file signed.")
' Verify the signature of the signed XML.
Console.WriteLine("Verifying signature...")
Dim result As Boolean = VerifyXmlFile("SignedExample.xml")
' Display the results of the signature verification to \
' the console.
If result Then
Console.WriteLine("The XML signature is valid.")
Else
Console.WriteLine("The XML signature is not valid.")
End If
Catch e As CryptographicException
Console.WriteLine(e.Message)
Finally
Key.Clear()
End Try
End Sub
' Sign an XML file and save the signature in a new file.
Sub SignXmlFile(ByVal FileName As String, ByVal SignedFileName As String, ByVal Key As RSA, ByVal XPathString As String)
' Create a new XML document.
Dim doc As New XmlDocument()
' Format the document to ignore white spaces.
doc.PreserveWhitespace = False
' Load the passed XML file using it's name.
doc.Load(New XmlTextReader(FileName))
' Create a SignedXml object.
Dim signedXml As New SignedXml(doc)
' Add the key to the SignedXml document.
signedXml.SigningKey = Key
' Create a reference to be signed.
Dim reference As New Reference()
reference.Uri = ""
' Create an XmlDsigXPathTransform object using
' the helper method 'CreateXPathTransform' defined
' later in this sample.
Dim XPathTransform As XmlDsigXPathTransform = CreateXPathTransform(XPathString)
' Add the transform to the reference.
reference.AddTransform(XPathTransform)
' Add the reference to the SignedXml object.
signedXml.AddReference(reference)
' Add an RSAKeyValue KeyInfo (optional; helps recipient find key to validate).
Dim keyInfo As New KeyInfo()
keyInfo.AddClause(New RSAKeyValue(CType(Key, RSA)))
signedXml.KeyInfo = keyInfo
' Compute the signature.
signedXml.ComputeSignature()
' Get the XML representation of the signature and save
' it to an XmlElement object.
Dim xmlDigitalSignature As XmlElement = signedXml.GetXml()
' Append the element to the XML document.
doc.DocumentElement.AppendChild(doc.ImportNode(xmlDigitalSignature, True))
' Save the signed XML document to a file specified
' using the passed string.
Dim xmltw As New XmlTextWriter(SignedFileName, New UTF8Encoding(False))
doc.WriteTo(xmltw)
xmltw.Close()
End Sub
' Verify the signature of an XML file and return the result.
Function VerifyXmlFile(ByVal Name As String) As [Boolean]
' Create a new XML document.
Dim xmlDocument As New XmlDocument()
' Format using white spaces.
xmlDocument.PreserveWhitespace = True
' Load the passed XML file into the document.
xmlDocument.Load(Name)
' Create a new SignedXml object and pass it
' the XML document class.
Dim signedXml As New SignedXml(xmlDocument)
' Find the "Signature" node and create a new
' XmlNodeList object.
Dim nodeList As XmlNodeList = xmlDocument.GetElementsByTagName("Signature")
' Load the signature node.
signedXml.LoadXml(CType(nodeList(0), XmlElement))
' Check the signature and return the result.
Return signedXml.CheckSignature()
End Function
' Create the XML that represents the transform.
Function CreateXPathTransform(ByVal XPathString As String) As XmlDsigXPathTransform
' Create a new XMLDocument object.
Dim doc As New XmlDocument()
' Create a new XmlElement.
Dim xPathElem As XmlElement = doc.CreateElement("XPath")
' Set the element text to the value
' of the XPath string.
xPathElem.InnerText = XPathString
' Create a new XmlDsigXPathTransform object.
Dim xForm As New XmlDsigXPathTransform()
' Load the XPath XML from the element.
xForm.LoadInnerXml(xPathElem.SelectNodes("."))
' Return the XML that represents the transform.
Return xForm
End Function
' Create example data to sign.
Sub CreateSomeXml(ByVal FileName As String)
' Create a new XmlDocument object.
Dim document As New XmlDocument()
' Create a new XmlNode object.
Dim node As XmlNode = document.CreateNode(XmlNodeType.Element, "", "MyXML", "Don't_Sign")
' Append the node to the document.
document.AppendChild(node)
' Create a new XmlNode object.
Dim subnode As XmlNode = document.CreateNode(XmlNodeType.Element, "", "TempElement", "Sign")
' Add some text to the node.
subnode.InnerText = "Here is some data to sign."
' Append the node to the document.
document.DocumentElement.AppendChild(subnode)
' Save the XML document to the file name specified.
Dim xmltw As New XmlTextWriter(FileName, New UTF8Encoding(False))
document.WriteTo(xmltw)
xmltw.Close()
End Sub
End Module
Esempio #2
using System;
using System.IO;
using System.Xml;
using System.Security.Cryptography;
using System.Security.Cryptography.Xml;
class Class1
{
[STAThread]
static void Main(string[] args)
{
// Encrypt a sample XML string.
XmlDocument productsXml = LoadProducts();
ShowTransformProperties(productsXml);
// Encrypt an XPath Xml string.
XmlDocument transformXml = LoadTransformByXml();
ShowTransformProperties(transformXml);
// Use XmlDsigXPathTransform to resolve a Uri.
Uri baseUri = new Uri("http://www.contoso.com");
string relativeUri = "xml";
Uri absoluteUri = ResolveUris(baseUri, relativeUri);
Console.WriteLine("This sample completed successfully; " +
"press Enter to exit.");
Console.ReadLine();
}
// Encrypt the text in the specified XmlDocument.
private static void ShowTransformProperties(XmlDocument xmlDoc)
{
// Create a new XMLDocument object.
XmlDocument doc = new XmlDocument();
// Create a new XmlElement.
XmlElement xPathElem = doc.CreateElement("XPath");
// Set the element text to the value
// of the XPath string.
xPathElem.InnerText = "ancestor-or-self::PRODUCTS";
// Create a new XmlDsigXPathTransform object.
XmlDsigXPathTransform xmlTransform = new XmlDsigXPathTransform();
// Load the XPath XML from the element.
xmlTransform.LoadInnerXml(xPathElem.SelectNodes("."));
// Ensure the transform is using the proper algorithm.
xmlTransform.Algorithm =
SignedXml.XmlDsigXPathTransformUrl;
// Retrieve the XML representation of the current transform.
XmlElement xmlInTransform = xmlTransform.GetXml();
Console.WriteLine("\nXml representation of the current transform: ");
Console.WriteLine(xmlInTransform.OuterXml);
// Retrieve the valid input types for the current transform.
Type[] validInTypes = xmlTransform.InputTypes;
// Verify the xmlTransform can accept the XMLDocument as an
// input type.
for (int i = 0; i < validInTypes.Length; i++)
{
if (validInTypes[i] == xmlDoc.GetType())
{
// Load the document into the transfrom.
xmlTransform.LoadInput(xmlDoc);
try
{
// This transform is created for demonstration purposes.
XmlDsigXPathTransform secondTransform =
new XmlDsigXPathTransform();
string classDescription = secondTransform.ToString();
xmlTransform.LoadInnerXml(xPathElem.SelectNodes(".")); ;
}
catch (CryptographicException)
{
Console.WriteLine("Caught exception while trying to " +
"load the specified Xml document. The document " +
"requires an XPath element to be valid.");
}
break;
}
}
Type[] validOutTypes = xmlTransform.OutputTypes;
for (int i = validOutTypes.Length - 1; i >= 0; i--)
{
if (validOutTypes[i] == typeof(System.Xml.XmlDocument))
{
try
{
Type xmlDocumentType = typeof(System.Xml.XmlDocument);
XmlDocument xmlDocumentOutput = (XmlDocument)
xmlTransform.GetOutput(xmlDocumentType);
// Display to the console the Xml before and after
// encryption.
Console.WriteLine("Result of the GetOutput method call" +
" from the current transform: " +
xmlDocumentOutput.OuterXml);
}
catch (Exception ex)
{
Console.WriteLine("Unexpected exception caught: " +
ex.ToString());
}
break;
}
else if (validOutTypes[i] == typeof(System.Xml.XmlNodeList))
{
try
{
Type xmlNodeListType = typeof(System.Xml.XmlNodeList);
XmlNodeList xmlNodes = (XmlNodeList)
xmlTransform.GetOutput(xmlNodeListType);
// Display to the console the Xml before and after
// encryption.
Console.WriteLine("Encoding the following message: " +
xmlDoc.InnerText);
Console.WriteLine("Nodes of the XmlNodeList retrieved " +
"from GetOutput:");
for (int j = 0; j < xmlNodes.Count; j++)
{
Console.WriteLine("Node " + j +
" has the following name: " +
xmlNodes.Item(j).Name +
" and the following InnerXml: " +
xmlNodes.Item(j).InnerXml);
}
}
catch (Exception ex)
{
Console.WriteLine("Unexpected exception caught: " +
ex.ToString());
}
break;
}
else
{
object outputObject = xmlTransform.GetOutput();
}
}
}
// Create an XML document for the dsig namespace.
private static XmlDocument LoadTransformByXml()
{
XmlDocument xmlDoc = new XmlDocument();
string transformXml = "<Signature><Reference URI=''><Transforms>";
transformXml += "<Transform><XPath ";
transformXml += "xmlns:dsig='http://www.w3.org/2000/09/xmldsig#'>";
transformXml += "not(ancestor-or-self::dsig:Signature)";
transformXml += "</XPath></Transform>";
transformXml += "</Transforms></Reference></Signature>";
xmlDoc.LoadXml(transformXml);
return xmlDoc;
}
// Create an XML document describing various products.
private static XmlDocument LoadProducts()
{
XmlDocument xmlDoc = new XmlDocument();
string contosoProducts = "<PRODUCTS>";
contosoProducts += "<PRODUCT><ID>123</ID>";
contosoProducts += "<DESCRIPTION>Router</DESCRIPTION></PRODUCT>";
contosoProducts += "<PRODUCT><ID>456</ID>";
contosoProducts += "<DESCRIPTION>Keyboard</DESCRIPTION></PRODUCT>";
contosoProducts += "<PRODUCT><ID>789</ID>";
contosoProducts += "<DESCRIPTION>Monitor</DESCRIPTION></PRODUCT>";
contosoProducts += "</PRODUCTS>";
xmlDoc.LoadXml(contosoProducts);
return xmlDoc;
}
// Resolve the specified base and relative Uri's .
private static Uri ResolveUris(Uri baseUri, string relativeUri)
{
XmlUrlResolver xmlResolver = new XmlUrlResolver();
xmlResolver.Credentials =
System.Net.CredentialCache.DefaultCredentials;
XmlDsigXPathTransform xmlTransform =
new XmlDsigXPathTransform();
xmlTransform.Resolver = xmlResolver;
Uri absoluteUri = xmlResolver.ResolveUri(baseUri, relativeUri);
if (absoluteUri != null)
{
Console.WriteLine(
"\nResolved the base Uri and relative Uri to the following:");
Console.WriteLine(absoluteUri.ToString());
}
else
{
Console.WriteLine(
"Unable to resolve the base Uri and relative Uri");
}
return absoluteUri;
}
}
Imports System.IO
Imports System.Xml
Imports System.Security.Cryptography
Imports System.Security.Cryptography.Xml
Class Class1
<STAThread()> _
Shared Sub Main(ByVal args() As String)
' Encrypt a sample XML string.
Dim productsXml As XmlDocument = LoadProducts()
ShowTransformProperties(productsXml)
' Encrypt an XPath Xml string.
Dim transformXml As XmlDocument = LoadTransformByXml()
ShowTransformProperties(transformXml)
' Use XmlDsigXPathTransform to resolve a Uri.
Dim baseUri As New Uri("http://www.contoso.com")
Dim relativeUri As String = "xml"
Dim absoluteUri As Uri = ResolveUris(baseUri, relativeUri)
Console.WriteLine("This sample completed successfully; " + "press Enter to exit.")
Console.ReadLine()
End Sub
' Encrypt the text in the specified XmlDocument.
Private Shared Sub ShowTransformProperties(ByVal xmlDoc As XmlDocument)
' Create a new XMLDocument object.
Dim doc As New XmlDocument()
' Create a new XmlElement.
Dim xPathElem As XmlElement = doc.CreateElement("XPath")
' Set the element text to the value
' of the XPath string.
xPathElem.InnerText = "ancestor-or-self::PRODUCTS"
' Create a new XmlDsigXPathTransform object.
Dim xmlTransform As New XmlDsigXPathTransform()
' Load the XPath XML from the element.
xmlTransform.LoadInnerXml(xPathElem.SelectNodes("."))
' Ensure the transform is using the proper algorithm.
xmlTransform.Algorithm = SignedXml.XmlDsigXPathTransformUrl
' Retrieve the XML representation of the current transform.
Dim xmlInTransform As XmlElement = xmlTransform.GetXml()
Console.WriteLine(vbLf + "Xml representation of the current transform: ")
Console.WriteLine(xmlInTransform.OuterXml)
' Retrieve the valid input types for the current transform.
Dim validInTypes As Type() = xmlTransform.InputTypes
' Verify the xmlTransform can accept the XMLDocument as an
' input type.
Dim i As Integer
For i = 0 To validInTypes.Length
If validInTypes(i).Equals(xmlDoc.GetType()) Then
' Load the document into the transfrom.
xmlTransform.LoadInput(xmlDoc)
Try
' This transform is created for demonstration purposes.
Dim secondTransform As New XmlDsigXPathTransform()
Dim classDescription As String = secondTransform.ToString()
xmlTransform.LoadInnerXml(xPathElem.SelectNodes("."))
Catch
Console.WriteLine("Caught exception while trying to " + "load the specified Xml document. The document " + "requires an XPath element to be valid.")
End Try
Exit For
End If
Next i
Dim validOutTypes As Type() = xmlTransform.OutputTypes
For i = validOutTypes.Length - 1 To 0 Step -1
If validOutTypes(i).Equals(GetType(System.Xml.XmlDocument)) Then
Try
Dim xmlDocumentType As Type = GetType(System.Xml.XmlDocument)
Dim xmlDocumentOutput As XmlDocument = CType(xmlTransform.GetOutput(xmlDocumentType), XmlDocument)
' Display to the console the Xml before and after
' encryption.
Console.WriteLine("Result of the GetOutput method call" + " from the current transform: " + xmlDocumentOutput.OuterXml)
Catch ex As Exception
Console.WriteLine("Unexpected exception caught: " + ex.ToString())
End Try
Exit For
ElseIf validOutTypes(i).Equals(GetType(System.Xml.XmlNodeList)) Then
Try
Dim xmlNodeListType As Type = GetType(System.Xml.XmlNodeList)
Dim xmlNodes As XmlNodeList = CType(xmlTransform.GetOutput(xmlNodeListType), XmlNodeList)
' Display to the console the Xml before and after
' encryption.
Console.WriteLine("Encoding the following message: " + xmlDoc.InnerText)
Console.WriteLine("Nodes of the XmlNodeList retrieved " + "from GetOutput:")
For j As Integer = 0 To xmlNodes.Count - 1
Console.WriteLine("Node " + j + " has the following name: " + xmlNodes.Item(j).Name + " and the following InnerXml: " + xmlNodes.Item(j).InnerXml)
Next
Catch ex As Exception
Console.WriteLine("Unexpected exception caught: " + ex.ToString())
End Try
Exit For
Else
Dim outputObject As Object = xmlTransform.GetOutput()
End If
Next i
End Sub
' Create an XML document for the dsig namespace.
Private Shared Function LoadTransformByXml() As XmlDocument
Dim xmlDoc As New XmlDocument()
Dim transformXml As String = "<Signature><Reference URI=''><Transforms>"
transformXml += "<Transform><XPath "
transformXml += "xmlns:dsig='http://www.w3.org/2000/09/xmldsig#'>"
transformXml += "not(ancestor-or-self::dsig:Signature)"
transformXml += "</XPath></Transform>"
transformXml += "</Transforms></Reference></Signature>"
xmlDoc.LoadXml(transformXml)
Return xmlDoc
End Function 'LoadTransformByXml
' Create an XML document describing various products.
Private Shared Function LoadProducts() As XmlDocument
Dim xmlDoc As New XmlDocument()
Dim contosoProducts As String = "<PRODUCTS>"
contosoProducts += "<PRODUCT><ID>123</ID>"
contosoProducts += "<DESCRIPTION>Router</DESCRIPTION></PRODUCT>"
contosoProducts += "<PRODUCT><ID>456</ID>"
contosoProducts += "<DESCRIPTION>Keyboard</DESCRIPTION></PRODUCT>"
contosoProducts += "<PRODUCT><ID>789</ID>"
contosoProducts += "<DESCRIPTION>Monitor</DESCRIPTION></PRODUCT>"
contosoProducts += "</PRODUCTS>"
xmlDoc.LoadXml(contosoProducts)
Return xmlDoc
End Function 'LoadProducts
' Resolve the specified base and relative Uri's .
Private Shared Function ResolveUris(ByVal baseUri As Uri, ByVal relativeUri As String) As Uri
Dim xmlResolver As New XmlUrlResolver()
xmlResolver.Credentials = System.Net.CredentialCache.DefaultCredentials
Dim xmlTransform As New XmlDsigXPathTransform()
xmlTransform.Resolver = xmlResolver
Dim absoluteUri As Uri = xmlResolver.ResolveUri(baseUri, relativeUri)
If Not (absoluteUri Is Nothing) Then
Console.WriteLine(vbLf + "Resolved the base Uri and relative Uri to the following:")
Console.WriteLine(absoluteUri.ToString())
Else
Console.WriteLine("Unable to resolve the base Uri and relative Uri")
End If
Return absoluteUri
End Function
End Class
Commenti
La XmlDsigXPathTransform classe consente di indirizzare un documento XML usando il linguaggio XPath. Questa classe usa un'espressione XPath per selezionare i nodi XML che si desidera firmare o crittografare rimuovendo tutte le altre da un'operazione di crittografia.
Usare la XmlDsigXPathTransform classe per firmare o crittografare parti specifiche di un documento XML usando un'espressione XPath. Per informazioni sull'inizializzazione della XmlDsigXPathTransform classe sul valore di una stringa di trasformazione XPath, vedere il LoadInnerXml metodo .
L'URI (Uniform Resource Identifier) che descrive la XmlDsigXPathTransform classe è definita dal XmlDsigXPathTransformUrl campo.
Per altre informazioni sulla trasformazione XPath, vedere Sezione 6.6.3 della specifica XMLDSIG W3C.
Costruttori
| XmlDsigXPathTransform() |
Inizializza una nuova istanza della classe XmlDsigXPathTransform. |
Proprietà
| Algorithm |
Ottiene o imposta l'URI (Uniform Resource Identifier) che identifica l'algoritmo utilizzato dalla trasformazione corrente. (Ereditato da Transform) |
| Context |
Ottiene o imposta un oggetto XmlElement che rappresenta il contesto del documento nel quale viene eseguito l'oggetto Transform corrente. (Ereditato da Transform) |
| InputTypes |
Ottiene una matrice di tipi che sono input validi del metodo LoadInput(Object) dell'oggetto XmlDsigXPathTransform corrente. |
| OutputTypes |
Ottiene una matrice di tipi che sono possibili output dei metodi GetOutput() dell'oggetto XmlDsigXPathTransform corrente. |
| PropagatedNamespaces |
Ottiene o imposta l'oggetto Hashtable che contiene gli spazi dei nomi propagati nella firma. (Ereditato da Transform) |
| Resolver |
Imposta l'oggetto XmlResolver corrente. (Ereditato da Transform) |
Metodi
| Equals(Object) |
Determina se l'oggetto specificato è uguale all'oggetto corrente. (Ereditato da Object) |
| GetDigestedOutput(HashAlgorithm) |
Quando è sottoposto a override in una classe derivata, restituisce il digest associato all'oggetto Transform. (Ereditato da Transform) |
| GetHashCode() |
Funge da funzione hash predefinita. (Ereditato da Object) |
| GetInnerXml() |
Viene restituita una rappresentazione XML dei parametri dell'oggetto XmlDsigXPathTransform che potranno essere inclusi come sottoelementi di un elemento |
| GetOutput() |
Restituisce l'output dell'oggetto XmlDsigXPathTransform corrente. |
| GetOutput(Type) |
Restituisce l'output dell'oggetto XmlDsigXPathTransform corrente di tipo XmlNodeList. |
| GetType() |
Ottiene l'oggetto Type dell'istanza corrente. (Ereditato da Object) |
| GetXml() |
Restituisce la rappresentazione XML dell'oggetto Transform corrente. (Ereditato da Transform) |
| LoadInnerXml(XmlNodeList) |
Consente di analizzare l'oggetto XmlNodeList specificato specificato come contenuto specifico della trasformazione di un elemento |
| LoadInput(Object) |
Consente di caricare l'input specificato nell'oggetto XmlDsigXPathTransform corrente. |
| MemberwiseClone() |
Crea una copia superficiale dell'oggetto Object corrente. (Ereditato da Object) |
| ToString() |
Restituisce una stringa che rappresenta l'oggetto corrente. (Ereditato da Object) |
Si applica a
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