XmlElementAttribute 构造函数

参考

定义

命名空间:: System.Xml.Serialization

程序集:: System.Xml.XmlSerializer.dll

程序集:: System.Xml.ReaderWriter.dll

程序集:: System.Xml.dll

程序集:: netstandard.dll

重要

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初始化 XmlElementAttribute 类的新实例。

重载

XmlElementAttribute()	初始化 XmlElementAttribute 类的新实例。
XmlElementAttribute(String)	初始化 XmlElementAttribute 类的新实例，并指定 XML 元素的名称。
XmlElementAttribute(Type)	初始化 XmlElementAttribute 类的新实例，并指定 XmlElementAttribute 所应用到的成员的类型。此类型在序列化或反序列化包含它的对象时由 XmlSerializer 使用。
XmlElementAttribute(String, Type)	初始化 XmlElementAttribute 的新实例，并指定 XML 元素的名称和 XmlElementAttribute 应用到的成员的派生类型。此成员类型在 XmlSerializer 序列化包含它的对象时使用。

XmlElementAttribute()

初始化 XmlElementAttribute 类的新实例。

public:
 XmlElementAttribute();

public XmlElementAttribute ();

Public Sub New ()

示例

以下示例将 XmlElementAttribute 类应用于该类。

public ref class MyClass
{
public:

   [XmlElement]
   String^ TeacherName;
};

public class MyClass
{
   [XmlElement()]
   public string TeacherName;
}

Public Class MyClass1
    <XmlElement()> Public TeacherName As String
End Class

适用于

XmlElementAttribute(String)

初始化 XmlElementAttribute 类的新实例，并指定 XML 元素的名称。

public:
 XmlElementAttribute(System::String ^ elementName);

public XmlElementAttribute (string elementName);

public XmlElementAttribute (string? elementName);

new System.Xml.Serialization.XmlElementAttribute : string -> System.Xml.Serialization.XmlElementAttribute

Public Sub New (elementName As String)

参数

elementName: String

序列化成员的 XML 元素名。

示例

以下示例显示了一个包含一个名为的字段 Vehicles的简单类。该示例将应用于 XmlElementAttribute 字段并包含 elementName 参数，从而指示 XmlSerializer 生成名为“Cars”而不是“Vehicles”的 XML 元素。

public ref class Transportation
{
public:

   [XmlElement("Cars")]
   String^ Vehicles;
};

public class Transportation
{
   [XmlElement("Cars")]
   public string Vehicles;
}

Public Class Transportation
    <XmlElement("Cars")> Public Vehicles As String
End Class

注解

默认情况下，序列化类实例时，将使用 XmlSerializer 成员名称作为 XML 元素名称。例如，名为 Vehicle 的字段生成名为 Vehicle 的 XML 元素。但是，如果需要其他元素，例如 Cars，将其传入 elementName 参数。

适用于

XmlElementAttribute(Type)

初始化 XmlElementAttribute 类的新实例，并指定 XmlElementAttribute 所应用到的成员的类型。此类型在序列化或反序列化包含它的对象时由 XmlSerializer 使用。

public:
 XmlElementAttribute(Type ^ type);

public XmlElementAttribute (Type type);

public XmlElementAttribute (Type? type);

new System.Xml.Serialization.XmlElementAttribute : Type -> System.Xml.Serialization.XmlElementAttribute

Public Sub New (type As Type)

参数

type: Type

从该成员的类型派生的对象的 Type。

示例

以下示例序列化一个名为包含 Orchestra 一 Instruments个名为的字段的类，该字段返回对象数组 Instrument 。名为 Brass 第二个类的类继承自 Instrument 该类。该示例将应用于XmlElementAttributeInstruments字段，并指定类型Brass，允许Instruments该字段接受Brass对象。该示例还通过设置 ElementName 属性来指定 XML 元素的名称。

#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 )
{
   // To write the file, a TextWriter is required.
   TextWriter^ writer = gcnew StreamWriter( filename );
   XmlAttributeOverrides^ attrOverrides = gcnew XmlAttributeOverrides;
   XmlAttributes^ attrs = gcnew XmlAttributes;

   // Creates an XmlElementAttribute that overrides the Instrument type.
   XmlElementAttribute^ attr = gcnew XmlElementAttribute( Brass::typeid );
   attr->ElementName = "Brass";

   // Adds the element to the collection of elements.
   attrs->XmlElements->Add( attr );
   attrOverrides->Add( Orchestra::typeid, "Instruments", attrs );

   // Creates the XmlSerializer using the XmlAttributeOverrides.
   XmlSerializer^ s = gcnew XmlSerializer( Orchestra::typeid,attrOverrides );

   // Creates the object to serialize.
   Orchestra^ band = gcnew Orchestra;

   // Creates an object of the derived type.
   Brass^ i = gcnew Brass;
   i->Name = "Trumpet";
   i->IsValved = true;
   array<Instrument^>^myInstruments = {i};
   band->Instruments = myInstruments;
   s->Serialize( writer, band );
   writer->Close();
}

void DeserializeObject( String^ filename )
{
   XmlAttributeOverrides^ attrOverrides = gcnew XmlAttributeOverrides;
   XmlAttributes^ attrs = gcnew XmlAttributes;

   // Creates an XmlElementAttribute that override the Instrument type.
   XmlElementAttribute^ attr = gcnew XmlElementAttribute( Brass::typeid );
   attr->ElementName = "Brass";

   // Adds the element to the collection of elements.
   attrs->XmlElements->Add( attr );
   attrOverrides->Add( Orchestra::typeid, "Instruments", attrs );

   // Creates 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:" );

   /* Deserializing differs from serializing. To read the 
      derived-object values, 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)
    {
      // To write the file, a TextWriter is required.
      TextWriter writer = new StreamWriter(filename);

      XmlAttributeOverrides attrOverrides =
         new XmlAttributeOverrides();
      XmlAttributes attrs = new XmlAttributes();

      // Creates an XmlElementAttribute that overrides the Instrument type.
      XmlElementAttribute attr = new
      XmlElementAttribute(typeof(Brass));
      attr.ElementName = "Brass";

      // Adds the element to the collection of elements.
      attrs.XmlElements.Add(attr);
      attrOverrides.Add(typeof(Orchestra), "Instruments", attrs);

      // Creates the XmlSerializer using the XmlAttributeOverrides.
      XmlSerializer s =
      new XmlSerializer(typeof(Orchestra), attrOverrides);

      // Creates the object to serialize.
      Orchestra band = new Orchestra();

      // Creates an object of the derived type.
      Brass i = new Brass();
      i.Name = "Trumpet";
      i.IsValved = true;
      Instrument[] myInstruments = {i};
      band.Instruments = myInstruments;
      s.Serialize(writer,band);
      writer.Close();
   }

   public void DeserializeObject(string filename)
   {
      XmlAttributeOverrides attrOverrides =
         new XmlAttributeOverrides();
      XmlAttributes attrs = new XmlAttributes();

      // Creates an XmlElementAttribute that override the Instrument type.
      XmlElementAttribute attr = new
      XmlElementAttribute(typeof(Brass));
      attr.ElementName = "Brass";

      // Adds the element to the collection of elements.
      attrs.XmlElements.Add(attr);
      attrOverrides.Add(typeof(Orchestra), "Instruments", attrs);

      // Creates 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:");

      /* Deserializing differs from serializing. To read the
         derived-object values, 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);
      }
   }
}

Option Strict
Option Explicit

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(filename As String)
        ' To write the file, a TextWriter is required.
        Dim writer As New StreamWriter(filename)
        
        Dim attrOverrides As New XmlAttributeOverrides()
        Dim attrs As New XmlAttributes()
        
        ' Creates an XmlElementAttribute that overrides the Instrument type.
        Dim attr As New XmlElementAttribute(GetType(Brass))
        attr.ElementName = "Brass"
        
        ' Adds the element to the collection of elements.
        attrs.XmlElements.Add(attr)
        attrOverrides.Add(GetType(Orchestra), "Instruments", attrs)
        
        ' Creates the XmlSerializer using the XmlAttributeOverrides.
        Dim s As New XmlSerializer(GetType(Orchestra), attrOverrides)
        
        ' Creates the object to serialize.
        Dim band As New Orchestra()
        
        ' Creates 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
        s.Serialize(writer, band)
        writer.Close()
    End Sub
    
    
    Public Sub DeserializeObject(filename As String)
        Dim attrOverrides As New XmlAttributeOverrides()
        Dim attrs As New XmlAttributes()
        
        ' Create an XmlElementAttribute that override the Instrument type.
        Dim attr As New XmlElementAttribute(GetType(Brass))
        attr.ElementName = "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:")
        
        ' Deserializing differs from serializing. To read the
        ' derived-object values, 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

注解

使用 type 参数指定派生自基类的类型。例如，假设一个名为 MyAnimal 的属性返回一个 Animal 对象。你想要增强对象，以便创建一 Mammal 个名为从 Animal 类继承的新类。若要指示XmlSerializer在序列化MyAnimal属性时接受Mammal该类，Type请将Mammal该类传递给构造函数。

适用于

XmlElementAttribute(String, Type)

初始化 XmlElementAttribute 的新实例，并指定 XML 元素的名称和 XmlElementAttribute 应用到的成员的派生类型。此成员类型在 XmlSerializer 序列化包含它的对象时使用。

public:
 XmlElementAttribute(System::String ^ elementName, Type ^ type);

public XmlElementAttribute (string elementName, Type type);

public XmlElementAttribute (string? elementName, Type? type);

new System.Xml.Serialization.XmlElementAttribute : string * Type -> System.Xml.Serialization.XmlElementAttribute

Public Sub New (elementName As String, type As Type)

参数

elementName: String