SoapAttributes.SoapDefaultValue Proprietà

Definizione

Spazio dei nomi:

System.Xml.Serialization

Assembly:

System.Xml.XmlSerializer.dll

Assembly:

System.Xml.dll

Assembly:

netstandard.dll

Ottiene o imposta il valore predefinito di un attributo o elemento XML.

public:
 property System::Object ^ SoapDefaultValue { System::Object ^ get(); void set(System::Object ^ value); };

public object? SoapDefaultValue { get; set; }

public object SoapDefaultValue { get; set; }

member this.SoapDefaultValue : obj with get, set

Public Property SoapDefaultValue As Object

Valore della proprietà

Object

Un oggetto che rappresenta il valore predefinito di un attributo o elemento XML.

Esempio

Nell'esempio seguente viene serializzato una classe denominata che include un campo denominato Group GroupName. Il valore predefinito è impostato su DefaultValueAttribute ".NET". Non impostando il campo o impostandolo su ".NET", il valore non viene serializzato (perché il valore predefinito è già noto). L'esempio esegue anche l'override del valore predefinito nel CreateOverrideSerializer metodo, chiamato dal SerializeOverride metodo . L'esempio chiama entrambi i metodi SerializeOriginal e SerializeOverrideimposta lo stesso valore (".NET") per il GroupName campo. A causa dell'override, il valore viene serializzato solo quando si chiama il SerializeOverride metodo.

#using <System.dll>
#using <System.Xml.dll>

using namespace System;
using namespace System::IO;
using namespace System::Xml;
using namespace System::Xml::Serialization;
using namespace System::Xml::Schema;
using namespace System::ComponentModel;
public ref class Group
{
public:

   // The default is set to .NET.

   [DefaultValue(".NET")]
   String^ GroupName;
};

public ref class Run
{
public:
   void SerializeOriginal( String^ filename )
   {
      // Create an instance of the XmlSerializer class.
      XmlSerializer^ mySerializer = gcnew XmlSerializer( Group::typeid );

      // Writing the file requires a TextWriter.
      TextWriter^ writer = gcnew StreamWriter( filename );

      // Create an instance of the class that will be serialized.
      Group^ myGroup = gcnew Group;

      // Setting the GroupName to '.NET' is like not setting it at all
      // because it is the default value. So no value will be 
      // serialized, and on deserialization it will appear as a blank.
      myGroup->GroupName = ".NET";

      // Serialize the class, and close the TextWriter.
      mySerializer->Serialize( writer, myGroup );
      writer->Close();
   }

   void SerializeOverride( String^ filename )
   {
      // Create an instance of the XmlSerializer class
      // that overrides the serialization.
      XmlSerializer^ overRideSerializer = CreateOverrideSerializer();

      // Writing the file requires a TextWriter.
      TextWriter^ writer = gcnew StreamWriter( filename );

      // Create an instance of the class that will be serialized.
      Group^ myGroup = gcnew Group;

      // The  specifies that the default value is now 
      // 'Team1'. So setting the GroupName to '.NET' means
      // the value will be serialized.
      myGroup->GroupName = ".NET";

      // Serialize the class, and close the TextWriter.
      overRideSerializer->Serialize( writer, myGroup );
      writer->Close();
   }

   void DeserializeOriginal( String^ filename )
   {
      // Create an instance of the XmlSerializer class.
      XmlSerializer^ mySerializer = gcnew XmlSerializer( Group::typeid );

      // Reading the file requires a TextReader.
      TextReader^ reader = gcnew StreamReader( filename );

      // Deserialize and cast the Object*.
      Group^ myGroup;
      myGroup = safe_cast<Group^>(mySerializer->Deserialize( reader ));
      Console::WriteLine( myGroup->GroupName );
      Console::WriteLine();
   }

   void DeserializeOverride( String^ filename )
   {
      // Create an instance of the XmlSerializer class.
      XmlSerializer^ overRideSerializer = CreateOverrideSerializer();

      // Reading the file requires a TextReader.
      TextReader^ reader = gcnew StreamReader( filename );

      // Deserialize and cast the Object*.
      Group^ myGroup;
      myGroup = safe_cast<Group^>(overRideSerializer->Deserialize( reader ));
      Console::WriteLine( myGroup->GroupName );
   }

private:
   XmlSerializer^ CreateOverrideSerializer()
   {
      SoapAttributeOverrides^ mySoapAttributeOverrides = gcnew SoapAttributeOverrides;
      SoapAttributes^ soapAtts = gcnew SoapAttributes;

      // Create a new DefaultValueAttribute Object* for the GroupName
      // property.
      DefaultValueAttribute^ newDefault = gcnew DefaultValueAttribute( "Team1" );
      soapAtts->SoapDefaultValue = newDefault;
      mySoapAttributeOverrides->Add( Group::typeid, "GroupName", soapAtts );

      // Create an XmlTypeMapping that is used to create an instance 
      // of the XmlSerializer. Then return the XmlSerializer Object*.
      XmlTypeMapping^ myMapping = (gcnew SoapReflectionImporter( mySoapAttributeOverrides ))->ImportTypeMapping( Group::typeid );
      XmlSerializer^ ser = gcnew XmlSerializer( myMapping );
      return ser;
   }
};

int main()
{
   Run^ test = gcnew Run;
   test->SerializeOriginal( "SoapOriginal.xml" );
   test->SerializeOverride( "mySoapAttributeOverridesideAttributes.xml" );
   test->DeserializeOriginal( "SoapOriginal.xml" );
   test->DeserializeOverride( "mySoapAttributeOverridesideAttributes.xml" );
}

using System;
using System.IO;
using System.Xml;
using System.Xml.Serialization;
using System.Xml.Schema;
using System.ComponentModel;

public class Group
{
   // The default is set to .NET.
   [DefaultValue(".NET")]
   public string GroupName;
}

public class Run
{
   public static void Main()
   {
      Run test = new Run();
      test.SerializeOriginal("SoapOriginal.xml");
      test.SerializeOverride("mySoapAttributeOverridesideAttributes.xml");
      test.DeserializeOriginal("SoapOriginal.xml");
      test.DeserializeOverride("mySoapAttributeOverridesideAttributes.xml");
   }
   public void SerializeOriginal(string filename)
   {
      // Create an instance of the XmlSerializer class.
      XmlSerializer mySerializer =
      new XmlSerializer(typeof(Group));

      // Writing the file requires a TextWriter.
      TextWriter writer = new StreamWriter(filename);

      // Create an instance of the class that will be serialized.
      Group myGroup = new Group();

      // Setting the GroupName to '.NET' is like not setting it at all
      // because it is the default value. So no value will be
      // serialized, and on deserialization it will appear as a blank.
      myGroup.GroupName = ".NET";

      // Serialize the class, and close the TextWriter.
      mySerializer.Serialize(writer, myGroup);
      writer.Close();
   }

   public void SerializeOverride(string filename)
   {
      // Create an instance of the XmlSerializer class
      // that overrides the serialization.
      XmlSerializer overRideSerializer = CreateOverrideSerializer();

      // Writing the file requires a TextWriter.
      TextWriter writer = new StreamWriter(filename);

      // Create an instance of the class that will be serialized.
      Group myGroup = new Group();

      // The override specifies that the default value is now
      // 'Team1'. So setting the GroupName to '.NET' means
      // the value will be serialized.
      myGroup.GroupName = ".NET";
      // Serialize the class, and close the TextWriter.
      overRideSerializer.Serialize(writer, myGroup);
       writer.Close();
   }

   public void DeserializeOriginal(string filename)
   {
      // Create an instance of the XmlSerializer class.
      XmlSerializer mySerializer= new XmlSerializer(typeof(Group));
      // Reading the file requires a TextReader.
      TextReader reader = new StreamReader(filename);

      // Deserialize and cast the object.
      Group myGroup;
      myGroup = (Group) mySerializer.Deserialize(reader);

      Console.WriteLine(myGroup.GroupName);
      Console.WriteLine();
   }

   public void DeserializeOverride(string filename)
   {
      // Create an instance of the XmlSerializer class.
      XmlSerializer overRideSerializer = CreateOverrideSerializer();
      // Reading the file requires a TextReader.
      TextReader reader = new StreamReader(filename);

      // Deserialize and cast the object.
      Group myGroup;
      myGroup = (Group) overRideSerializer.Deserialize(reader);

      Console.WriteLine(myGroup.GroupName);
   }

   private XmlSerializer CreateOverrideSerializer()
   {
      SoapAttributeOverrides mySoapAttributeOverrides =
      new SoapAttributeOverrides();
      SoapAttributes soapAtts = new SoapAttributes();
      // Create a new DefaultValueAttribute object for the GroupName
      // property.
      DefaultValueAttribute newDefault =
      new DefaultValueAttribute("Team1");
      soapAtts.SoapDefaultValue = newDefault;

      mySoapAttributeOverrides.Add(typeof(Group), "GroupName",
      soapAtts);

      // Create an XmlTypeMapping that is used to create an instance
      // of the XmlSerializer. Then return the XmlSerializer object.
      XmlTypeMapping myMapping = (new SoapReflectionImporter(
      mySoapAttributeOverrides)).ImportTypeMapping(typeof(Group));
    
      XmlSerializer ser = new XmlSerializer(myMapping);
      return ser;
   }
}

Imports System.IO
Imports System.Xml
Imports System.Xml.Serialization
Imports System.Xml.Schema
Imports System.ComponentModel

Public Class Group
   ' The default is set to .NET.
   <DefaultValue(".NET")> _
   Public GroupName As String
End Class
 
Public Class Run

   Public Shared Sub Main()
   
      Dim test As Run = new Run()
      test.SerializeOriginal("SoapOriginal.xml")
      test.SerializeOverride _
      ("mySoapAttributeOverridesideAttributes.xml")
      test.DeserializeOriginal("SoapOriginal.xml")
      test.DeserializeOverride _
      ("mySoapAttributeOverridesideAttributes.xml")
   End Sub
   
   public Sub SerializeOriginal(filename As String)
       ' Create an instance of the XmlSerializer class.
      Dim mySerializer As XmlSerializer =  _
      new XmlSerializer(GetType(Group))

      ' Writing the file requires a TextWriter.
      Dim writer As TextWriter = new StreamWriter(filename)

      ' Create an instance of the class that will be serialized.
      Dim myGroup As Group = new Group()

      ' Setting the GroupName to '.NET' is like not setting it at all
      ' because it is the default value. So no value will be 
      ' serialized, and on deserialization it will appear as a blank.
      myGroup.GroupName = ".NET"

      ' Serialize the class, and close the TextWriter.
      mySerializer.Serialize(writer, myGroup)
      writer.Close()
   End Sub

   Public Sub SerializeOverride(filename As String)
   
      ' Create an instance of the XmlSerializer class
      ' that overrides the serialization.
      Dim overRideSerializer As XmlSerializer = CreateOverrideSerializer()

      ' Writing the file requires a TextWriter.
      Dim writer As TextWriter = new StreamWriter(filename)

      ' Create an instance of the class that will be serialized.
      Dim myGroup As Group = new Group()

      ' The override specifies that the default value is now 
      ' 'Team1'. So setting the GroupName to '.NET' means
      ' the value will be serialized.
      myGroup.GroupName = ".NET"
      ' Serialize the class, and close the TextWriter.
      overRideSerializer.Serialize(writer, myGroup)
       writer.Close()

   End Sub


   Public Sub DeserializeOriginal(filename As String)
   
      ' Create an instance of the XmlSerializer class.
      Dim mySerializer As XmlSerializer = new XmlSerializer(GetType(Group))
      ' Reading the file requires a TextReader.
      Dim reader As TextReader = new StreamReader(filename)

      ' Deserialize and cast the object.
      Dim myGroup As Group = CType(mySerializer.Deserialize(reader), Group)

      Console.WriteLine(myGroup.GroupName)
      Console.WriteLine()
   End Sub

   Public Sub DeserializeOverride(filename As String)
   
      ' Create an instance of the XmlSerializer class.
      Dim overRideSerializer As XmlSerializer = CreateOverrideSerializer()
      ' Reading the file requires a TextReader.
      Dim reader As TextReader = new StreamReader(filename)

      ' Deserialize and cast the object.
      Dim myGroup As Group = CType(overRideSerializer.Deserialize(reader), Group)

      Console.WriteLine(myGroup.GroupName)

   End Sub

   Private Function CreateOverrideSerializer() As XmlSerializer 
   
      Dim mySoapAttributeOverrides As SoapAttributeOverrides  = _
      New SoapAttributeOverrides()
      Dim soapAtts As SoapAttributes = New SoapAttributes()
      ' Create a new DefaultValueAttribute object for the GroupName
      ' property.
      Dim newDefault As DefaultValueAttribute = _
      new DefaultValueAttribute("Team1")
      soapAtts.SoapDefaultValue = newDefault

     mySoapAttributeOverrides.Add(GetType(Group), "GroupName", _
     soapAtts)
      
      ' Create an XmlTypeMapping that is used to create an instance 
      ' of the XmlSerializer. Then return the XmlSerializer object.
      Dim myMapping As XmlTypeMapping = _
      (New SoapReflectionImporter( _
      mySoapAttributeOverrides)).ImportTypeMapping(GetType(Group))
    
      Dim ser As XmlSerializer = new XmlSerializer(myMapping)
      return ser
   End Function
End Class

Commenti

Il valore predefinito di un membro può essere impostato applicando un DefaultValueAttribute attributo al membro. Se il membro viene serializzato come messaggio SOAP codificato, è possibile modificare il valore predefinito creando una nuova DefaultValueAttributeproprietà , impostandone Value la proprietà e impostando la SoapDefaultValue proprietà sull'oggetto. Aggiungere l'oggetto SoapAttributes a un SoapAttributeOverridesoggetto . Per altre informazioni, vedere la panoramica della SoapAttributeOverrides classe.

Vedi anche

• XmlAttributes
• Attributi per il controllo della serializzazione SOAP codificata
• Procedura: serializzare un oggetto come flusso XML con codifica SOAP