XmlAttributes Конструкторы
Определение
Важно!
Некоторые сведения относятся к предварительной версии продукта, в которую до выпуска могут быть внесены существенные изменения. Майкрософт не предоставляет никаких гарантий, явных или подразумеваемых, относительно приведенных здесь сведений.
Инициализирует новый экземпляр класса XmlAttributes.
Перегрузки
XmlAttributes() |
Инициализирует новый экземпляр класса XmlAttributes. |
XmlAttributes(ICustomAttributeProvider) |
Инициализация нового экземпляра класса XmlAttributes и настройка сериализации и десериализации объекта с помощью XmlSerializer. |
XmlAttributes()
Инициализирует новый экземпляр класса XmlAttributes.
public:
XmlAttributes();
public XmlAttributes ();
Public Sub New ()
Примеры
В следующем примере сериализуется экземпляр класса с именем Orchestra
, который содержит одно поле с именем Instruments
, которое возвращает массив Instrument
объектов. Второй класс с именем Brass
наследует от Instrument
класса. В этом примере создается XmlAttributes объект для переопределения Instrument
поля, позволяя полю принимать Brass
объекты и добавляет XmlAttributes объект в экземпляр XmlAttributeOverrides класса.
#using <System.Xml.dll>
#using <System.dll>
using namespace System;
using namespace System::IO;
using namespace System::Xml::Serialization;
public ref class Instrument
{
public:
String^ Name;
};
public ref class Brass: public Instrument
{
public:
bool IsValved;
};
public ref class Orchestra
{
public:
array<Instrument^>^Instruments;
};
void SerializeObject( String^ filename )
{
/* Each overridden field, property, or type requires
an XmlAttributes object. */
XmlAttributes^ attrs = gcnew XmlAttributes;
/* Create an XmlElementAttribute to override the
field that returns Instrument objects. The overridden field
returns Brass objects instead. */
XmlElementAttribute^ attr = gcnew XmlElementAttribute;
attr->ElementName = "Brass";
attr->Type = Brass::typeid;
// Add the element to the collection of elements.
attrs->XmlElements->Add( attr );
// Create the XmlAttributeOverrides object.
XmlAttributeOverrides^ attrOverrides = gcnew XmlAttributeOverrides;
/* Add the type of the class that contains the overridden
member and the XmlAttributes to override it with to the
XmlAttributeOverrides object. */
attrOverrides->Add( Orchestra::typeid, "Instruments", attrs );
// Create the XmlSerializer using the XmlAttributeOverrides.
XmlSerializer^ s = gcnew XmlSerializer( Orchestra::typeid,attrOverrides );
// Writing the file requires a TextWriter.
TextWriter^ writer = gcnew StreamWriter( filename );
// Create the object that will be serialized.
Orchestra^ band = gcnew Orchestra;
// Create an object of the derived type.
Brass^ i = gcnew Brass;
i->Name = "Trumpet";
i->IsValved = true;
array<Instrument^>^myInstruments = {i};
band->Instruments = myInstruments;
// Serialize the object.
s->Serialize( writer, band );
writer->Close();
}
void DeserializeObject( String^ filename )
{
XmlAttributeOverrides^ attrOverrides = gcnew XmlAttributeOverrides;
XmlAttributes^ attrs = gcnew XmlAttributes;
// Create an XmlElementAttribute to override the Instrument.
XmlElementAttribute^ attr = gcnew XmlElementAttribute;
attr->ElementName = "Brass";
attr->Type = Brass::typeid;
// Add the element to the collection of elements.
attrs->XmlElements->Add( attr );
attrOverrides->Add( Orchestra::typeid, "Instruments", attrs );
// Create the XmlSerializer using the XmlAttributeOverrides.
XmlSerializer^ s = gcnew XmlSerializer( Orchestra::typeid,attrOverrides );
FileStream^ fs = gcnew FileStream( filename,FileMode::Open );
Orchestra^ band = dynamic_cast<Orchestra^>(s->Deserialize( fs ));
Console::WriteLine( "Brass:" );
/* The difference between deserializing the overridden
XML document and serializing it is this: To read the derived
object values, you must declare an object of the derived type
(Brass), and cast the Instrument instance to it. */
Brass^ b;
System::Collections::IEnumerator^ myEnum = band->Instruments->GetEnumerator();
while ( myEnum->MoveNext() )
{
Instrument^ i = safe_cast<Instrument^>(myEnum->Current);
b = dynamic_cast<Brass^>(i);
Console::WriteLine( "{0}\n{1}", b->Name, b->IsValved );
}
}
int main()
{
SerializeObject( "Override.xml" );
DeserializeObject( "Override.xml" );
}
using System;
using System.IO;
using System.Xml.Serialization;
public class Orchestra
{
public Instrument[] Instruments;
}
public class Instrument
{
public string Name;
}
public class Brass:Instrument
{
public bool IsValved;
}
public class Run
{
public static void Main()
{
Run test = new Run();
test.SerializeObject("Override.xml");
test.DeserializeObject("Override.xml");
}
public void SerializeObject(string filename)
{
/* Each overridden field, property, or type requires
an XmlAttributes object. */
XmlAttributes attrs = new XmlAttributes();
/* Create an XmlElementAttribute to override the
field that returns Instrument objects. The overridden field
returns Brass objects instead. */
XmlElementAttribute attr = new XmlElementAttribute();
attr.ElementName = "Brass";
attr.Type = typeof(Brass);
// Add the element to the collection of elements.
attrs.XmlElements.Add(attr);
// Create the XmlAttributeOverrides object.
XmlAttributeOverrides attrOverrides = new XmlAttributeOverrides();
/* Add the type of the class that contains the overridden
member and the XmlAttributes to override it with to the
XmlAttributeOverrides object. */
attrOverrides.Add(typeof(Orchestra), "Instruments", attrs);
// Create the XmlSerializer using the XmlAttributeOverrides.
XmlSerializer s =
new XmlSerializer(typeof(Orchestra), attrOverrides);
// Writing the file requires a TextWriter.
TextWriter writer = new StreamWriter(filename);
// Create the object that will be serialized.
Orchestra band = new Orchestra();
// Create an object of the derived type.
Brass i = new Brass();
i.Name = "Trumpet";
i.IsValved = true;
Instrument[] myInstruments = {i};
band.Instruments = myInstruments;
// Serialize the object.
s.Serialize(writer,band);
writer.Close();
}
public void DeserializeObject(string filename)
{
XmlAttributeOverrides attrOverrides =
new XmlAttributeOverrides();
XmlAttributes attrs = new XmlAttributes();
// Create an XmlElementAttribute to override the Instrument.
XmlElementAttribute attr = new XmlElementAttribute();
attr.ElementName = "Brass";
attr.Type = typeof(Brass);
// Add the element to the collection of elements.
attrs.XmlElements.Add(attr);
attrOverrides.Add(typeof(Orchestra), "Instruments", attrs);
// Create the XmlSerializer using the XmlAttributeOverrides.
XmlSerializer s =
new XmlSerializer(typeof(Orchestra), attrOverrides);
FileStream fs = new FileStream(filename, FileMode.Open);
Orchestra band = (Orchestra) s.Deserialize(fs);
Console.WriteLine("Brass:");
/* The difference between deserializing the overridden
XML document and serializing it is this: To read the derived
object values, you must declare an object of the derived type
(Brass), and cast the Instrument instance to it. */
Brass b;
foreach(Instrument i in band.Instruments)
{
b = (Brass)i;
Console.WriteLine(
b.Name + "\n" +
b.IsValved);
}
}
}
Imports System.IO
Imports System.Xml.Serialization
Public Class Orchestra
Public Instruments() As Instrument
End Class
Public Class Instrument
Public Name As String
End Class
Public Class Brass
Inherits Instrument
Public IsValved As Boolean
End Class
Public Class Run
Public Shared Sub Main()
Dim test As New Run()
test.SerializeObject("Override.xml")
test.DeserializeObject("Override.xml")
End Sub
Public Sub SerializeObject(ByVal filename As String)
' Each overridden field, property, or type requires
' an XmlAttributes object.
Dim attrs As New XmlAttributes()
' Create an XmlElementAttribute to override the
' field that returns Instrument objects. The overridden field
' returns Brass objects instead.
Dim attr As New XmlElementAttribute()
attr.ElementName = "Brass"
attr.Type = GetType(Brass)
' Add the element to the collection of elements.
attrs.XmlElements.Add(attr)
' Create the XmlAttributeOverrides object.
Dim attrOverrides As New XmlAttributeOverrides()
' Add the type of the class that contains the overridden
' member and the XmlAttributes to override it with to the
' XmlAttributeOverrides object.
attrOverrides.Add(GetType(Orchestra), "Instruments", attrs)
' Create the XmlSerializer using the XmlAttributeOverrides.
Dim s As New XmlSerializer(GetType(Orchestra), attrOverrides)
' Writing the file requires a TextWriter.
Dim writer As New StreamWriter(filename)
' Create the object that will be serialized.
Dim band As New Orchestra()
' Create an object of the derived type.
Dim i As New Brass()
i.Name = "Trumpet"
i.IsValved = True
Dim myInstruments() As Instrument = {i}
band.Instruments = myInstruments
' Serialize the object.
s.Serialize(writer, band)
writer.Close()
End Sub
Public Sub DeserializeObject(ByVal filename As String)
Dim attrOverrides As New XmlAttributeOverrides()
Dim attrs As New XmlAttributes()
' Create an XmlElementAttribute to override the Instrument.
Dim attr As New XmlElementAttribute()
attr.ElementName = "Brass"
attr.Type = GetType(Brass)
' Add the element to the collection of elements.
attrs.XmlElements.Add(attr)
attrOverrides.Add(GetType(Orchestra), "Instruments", attrs)
' Create the XmlSerializer using the XmlAttributeOverrides.
Dim s As New XmlSerializer(GetType(Orchestra), attrOverrides)
Dim fs As New FileStream(filename, FileMode.Open)
Dim band As Orchestra = CType(s.Deserialize(fs), Orchestra)
Console.WriteLine("Brass:")
' The difference between deserializing the overridden
' XML document and serializing it is this: To read the derived
' object values, you must declare an object of the derived type
' (Brass), and cast the Instrument instance to it.
Dim b As Brass
Dim i As Instrument
For Each i In band.Instruments
b = CType(i, Brass)
Console.WriteLine(b.Name + ControlChars.Cr + _
b.IsValved.ToString())
Next i
End Sub
End Class
Применяется к
XmlAttributes(ICustomAttributeProvider)
Инициализация нового экземпляра класса XmlAttributes и настройка сериализации и десериализации объекта с помощью XmlSerializer.
public:
XmlAttributes(System::Reflection::ICustomAttributeProvider ^ provider);
public XmlAttributes (System.Reflection.ICustomAttributeProvider provider);
new System.Xml.Serialization.XmlAttributes : System.Reflection.ICustomAttributeProvider -> System.Xml.Serialization.XmlAttributes
Public Sub New (provider As ICustomAttributeProvider)
Параметры
- provider
- ICustomAttributeProvider
Класс, представляющий альтернативный вариант реализации атрибутов, управляющих сериализацией XML.
Комментарии
Используйте конструктор без параметров для XmlAttributes класса, а не этот конструктор.