XmlSchemaKeyref Class
TOC
Collapse the table of content
Expand the table of content

XmlSchemaKeyref Class

Identifies a keyref constraint. Represents the World Wide Web Consortium (W3C) keyref element.

For a list of all members of this type, see XmlSchemaKeyref Members.

System.Object
   System.Xml.Schema.XmlSchemaObject
      System.Xml.Schema.XmlSchemaAnnotated
         System.Xml.Schema.XmlSchemaIdentityConstraint
            System.Xml.Schema.XmlSchemaKeyref

[Visual Basic]
Public Class XmlSchemaKeyref
   Inherits XmlSchemaIdentityConstraint
[C#]
public class XmlSchemaKeyref : XmlSchemaIdentityConstraint
[C++]
public __gc class XmlSchemaKeyref : public
   XmlSchemaIdentityConstraint
[JScript]
public class XmlSchemaKeyref extends XmlSchemaIdentityConstraint

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Remarks

Specifies that an attribute or element value (or set of values) have a correspondence with those of the specified key or unique element. The constraint name must be unique within a schema.

Example

[Visual Basic, C#, C++] The following example creates a key element.

[Visual Basic] 
Imports System
Imports System.Collections
Imports System.IO
Imports System.Xml
Imports System.Xml.Xsl
Imports System.Xml.Schema

Public Class XmlSchemaObjectGenerator
   
   Private Shared Sub ValidationCallback(sender As Object, args As ValidationEventArgs)
      
      If args.Severity = XmlSeverityType.Warning Then
         Console.Write("WARNING: ")
      Else
         If args.Severity = XmlSeverityType.Error Then
            Console.Write("ERROR: ")
         End If 
      End If
      Console.WriteLine(args.Message)
   End Sub 'ValidationCallback
   
   
   
   Public Shared Sub Main()
      
      
      Dim tr As New XmlTextReader("empty.xsd")
      Dim schema As XmlSchema = XmlSchema.Read(tr, New ValidationEventHandler(AddressOf ValidationCallback))
      
      schema.ElementFormDefault = XmlSchemaForm.Qualified
      
      schema.TargetNamespace = "http://www.example.com/Report"
      
      If (True) Then
         
         Dim element As New XmlSchemaElement()
         element.Name = "purchaseReport"
         
         Dim element_complexType As New XmlSchemaComplexType()
         
         Dim element_complexType_sequence As New XmlSchemaSequence()
         
         If (True) Then
            
            Dim element_complexType_sequence_element As New XmlSchemaElement()
            element_complexType_sequence_element.Name = "region"
            element_complexType_sequence_element.SchemaTypeName = New XmlQualifiedName("string", "http://www.w3.org/2001/XMLSchema")
            
            If (True) Then
               
               Dim element_complexType_sequence_element_keyref As New XmlSchemaKeyref()
               element_complexType_sequence_element_keyref.Name = "dummy2"
               element_complexType_sequence_element_keyref.Selector = New XmlSchemaXPath()
               element_complexType_sequence_element_keyref.Selector.XPath = "r:zip/r:part"
               
               If (True) Then
                  Dim field As New XmlSchemaXPath()
                  
                  field.XPath = "@number"
                  element_complexType_sequence_element_keyref.Fields.Add(field)
               End If
               element_complexType_sequence_element_keyref.Refer = New XmlQualifiedName("pNumKey", "http://www.example.com/Report")
               element_complexType_sequence_element.Constraints.Add(element_complexType_sequence_element_keyref)
            End If
            element_complexType_sequence.Items.Add(element_complexType_sequence_element)
         End If
         element_complexType.Particle = element_complexType_sequence
         
         If (True) Then
            
            Dim element_complexType_attribute As New XmlSchemaAttribute()
            element_complexType_attribute.Name = "periodEnding"
            element_complexType_attribute.SchemaTypeName = New XmlQualifiedName("date", "http://www.w3.org/2001/XMLSchema")
            element_complexType.Attributes.Add(element_complexType_attribute)
         End If
         element.SchemaType = element_complexType
         
         If (True) Then
            
            Dim element_key As New XmlSchemaKey()
            element_key.Name = "pNumKey"
            element_key.Selector = New XmlSchemaXPath()
            element_key.Selector.XPath = "r:parts/r:part"
            
            If (True) Then
               Dim field As New XmlSchemaXPath()
               
               field.XPath = "@number"
               element_key.Fields.Add(field)
            End If
            element.Constraints.Add(element_key)
         End If
         
         schema.Items.Add(element)
      End If
      
      schema.Write(Console.Out)
   End Sub 'Main 
End Class 'XmlSchemaObjectGenerator 

' Main() 

'XmlSchemaObjectGenerator

[C#] 
using System;
using System.Collections;
using System.IO;
using System.Xml;
using System.Xml.Xsl;
using System.Xml.Schema;

public class XmlSchemaObjectGenerator {
  
  

    private static void ValidationCallback(object sender, ValidationEventArgs args ){
  
    if(args.Severity == XmlSeverityType.Warning)
        Console.Write("WARNING: ");
    else if(args.Severity == XmlSeverityType.Error)
        Console.Write("ERROR: ");
  
    Console.WriteLine(args.Message);
    }
                      
            
    public static void Main() {
               
         
      XmlTextReader tr = new XmlTextReader("empty.xsd");
        XmlSchema schema = XmlSchema.Read(tr, new ValidationEventHandler(ValidationCallback));
        
            schema.ElementFormDefault = XmlSchemaForm.Qualified;
        
            schema.TargetNamespace = "http://www.example.com/Report";
        
            {
                
        XmlSchemaElement element = new XmlSchemaElement();
        element.Name = "purchaseReport";
        
        XmlSchemaComplexType element_complexType = new XmlSchemaComplexType();
        
        XmlSchemaSequence element_complexType_sequence = new XmlSchemaSequence();
        
            {
                
        XmlSchemaElement element_complexType_sequence_element = new XmlSchemaElement();
        element_complexType_sequence_element.Name = "region";
        element_complexType_sequence_element.SchemaTypeName = 
                new XmlQualifiedName("string", "http://www.w3.org/2001/XMLSchema")
            ;
        
            {
                
        XmlSchemaKeyref element_complexType_sequence_element_keyref = new XmlSchemaKeyref();
        element_complexType_sequence_element_keyref.Name = "dummy2";
        element_complexType_sequence_element_keyref.Selector = new XmlSchemaXPath();
            element_complexType_sequence_element_keyref.Selector.XPath = "r:zip/r:part";
        
            {
                XmlSchemaXPath field = new XmlSchemaXPath();
                
                field.XPath = "@number";
                element_complexType_sequence_element_keyref.Fields.Add(field);
            }
        element_complexType_sequence_element_keyref.Refer =  
                new XmlQualifiedName("pNumKey", "http://www.example.com/Report")
            ;
        element_complexType_sequence_element.Constraints.Add(element_complexType_sequence_element_keyref);
            }
        element_complexType_sequence.Items.Add(element_complexType_sequence_element);
            }
        element_complexType.Particle = element_complexType_sequence;
        
            {
                
        XmlSchemaAttribute element_complexType_attribute = new XmlSchemaAttribute();
        element_complexType_attribute.Name = "periodEnding";
        element_complexType_attribute.SchemaTypeName = 
                new XmlQualifiedName("date", "http://www.w3.org/2001/XMLSchema")
            ;
        element_complexType.Attributes.Add(element_complexType_attribute);
            }
        element.SchemaType = element_complexType;
        
            {
                
        XmlSchemaKey element_key = new XmlSchemaKey();
        element_key.Name = "pNumKey";
        element_key.Selector = new XmlSchemaXPath();
            element_key.Selector.XPath = "r:parts/r:part";
        
            {
                XmlSchemaXPath field = new XmlSchemaXPath();
                
                field.XPath = "@number";
                element_key.Fields.Add(field);
            }
        element.Constraints.Add(element_key);
            }
        
                schema.Items.Add(element);
            }
        
        schema.Write(Console.Out);

         

    }/* Main() */ 

} 
//XmlSchemaObjectGenerator

[C++] 
#using <mscorlib.dll>
#using <System.Xml.dll>
using namespace System;
using namespace System::Collections;
using namespace System::IO;
using namespace System::Xml;
using namespace System::Xml::Xsl;
using namespace System::Xml::Schema;

__gc public class XmlSchemaObjectGenerator
{
public:
   static void ValidationCallback(Object* /*sender*/, ValidationEventArgs * args)
   {
      if (args -> Severity == XmlSeverityType::Warning)
         Console::Write(S"WARNING: ");
      else if (args -> Severity == XmlSeverityType::Error)
         Console::Write(S"ERROR: ");
      Console::WriteLine(args -> Message);
   }
}; // XmlSchemaObjectGenerator

int main()
{
   XmlTextReader* tr = new XmlTextReader(S"empty.xsd");
   XmlSchema * schema = XmlSchema::Read(tr, new ValidationEventHandler(schema, XmlSchemaObjectGenerator::ValidationCallback));

   schema -> ElementFormDefault = XmlSchemaForm::Qualified;

   schema -> TargetNamespace = S"http://www.example.com/Report";
   {
      XmlSchemaElement* element = new XmlSchemaElement();
      element -> Name = S"purchaseReport";

      XmlSchemaComplexType* element_complexType = new XmlSchemaComplexType();

      XmlSchemaSequence* element_complexType_sequence = new XmlSchemaSequence();
      {
         XmlSchemaElement* element_complexType_sequence_element = new XmlSchemaElement();
         element_complexType_sequence_element -> Name = S"region";
         element_complexType_sequence_element -> SchemaTypeName = new XmlQualifiedName(S"String*", S"http://www.w3.org/2001/XMLSchema");
         {
            XmlSchemaKeyref* element_complexType_sequence_element_keyref = new XmlSchemaKeyref();
            element_complexType_sequence_element_keyref -> Name = S"dummy2";
            element_complexType_sequence_element_keyref -> Selector = new XmlSchemaXPath();
            element_complexType_sequence_element_keyref -> Selector -> XPath = S"r:zip/r:part";
            {
               XmlSchemaXPath* field = new XmlSchemaXPath();
               field -> XPath = S"@number";
               element_complexType_sequence_element_keyref -> Fields->Add(field);
            }
            element_complexType_sequence_element_keyref -> Refer = new XmlQualifiedName(S"pNumKey", S"http://www.example.com/Report");
            element_complexType_sequence_element -> Constraints->Add(element_complexType_sequence_element_keyref);
         }
         element_complexType_sequence -> Items->Add(element_complexType_sequence_element);
      }
      element_complexType -> Particle = element_complexType_sequence;
      {
         XmlSchemaAttribute* element_complexType_attribute = new XmlSchemaAttribute();
         element_complexType_attribute -> Name = S"periodEnding";
         element_complexType_attribute -> SchemaTypeName = new XmlQualifiedName(S"date", S"http://www.w3.org/2001/XMLSchema");
         element_complexType -> Attributes->Add(element_complexType_attribute);
      }
      element -> SchemaType = element_complexType;
      {
         XmlSchemaKey* element_key = new XmlSchemaKey();
         element_key -> Name = S"pNumKey";
         element_key -> Selector = new XmlSchemaXPath();
         element_key -> Selector -> XPath = S"r:parts/r:part";
       {
          XmlSchemaXPath* field = new XmlSchemaXPath();
          field -> XPath = S"@number";
          element_key -> Fields->Add(field);
       }
       element -> Constraints->Add(element_key);
      }
      schema -> Items->Add(element);
   }
   schema -> Write(Console::Out);
} // main

[Visual Basic, C#, C++] The following XML file is generated for the preceding code example.

<?xml version="1.0" encoding="IBM437"?>
<xs:schema xmlns:r="http://www.example.com/Report" elementFormDefault="qualified" targetNamespace="http://www.example.com/Report" xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:element name="purchaseReport">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="region" type="xs:string">
          <xs:keyref name="dummy2" refer="r:pNumKey">
            <xs:selector xpath="r:zip/r:part" />
            <xs:field xpath="@number" />
          </xs:keyref>
        </xs:element>
      </xs:sequence>
      <xs:attribute name="periodEnding" type="xs:date" />
    </xs:complexType>
    <xs:key name="pNumKey">
      <xs:selector xpath="r:parts/r:part" />
      <xs:field xpath="@number" />
    </xs:key>
  </xs:element>
</xs:schema>

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Namespace: System.Xml.Schema

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

Assembly: System.Xml (in System.Xml.dll)

See Also

XmlSchemaKeyref Members | System.Xml.Schema Namespace

Show:
© 2016 Microsoft