XmlArrayAttribute Třída

Definice

Určuje, že XmlSerializer musí serializovat konkrétní člen třídy jako pole prvků XML.Specifies that the XmlSerializer must serialize a particular class member as an array of XML elements.

public ref class XmlArrayAttribute : Attribute
[System.AttributeUsage(System.AttributeTargets.Field | System.AttributeTargets.Parameter | System.AttributeTargets.Property | System.AttributeTargets.ReturnValue, AllowMultiple=false)]
public class XmlArrayAttribute : Attribute
public class XmlArrayAttribute : Attribute
[System.AttributeUsage(System.AttributeTargets.Field | System.AttributeTargets.Parameter | System.AttributeTargets.Property | System.AttributeTargets.ReturnValue)]
public class XmlArrayAttribute : Attribute
[<System.AttributeUsage(System.AttributeTargets.Field | System.AttributeTargets.Parameter | System.AttributeTargets.Property | System.AttributeTargets.ReturnValue, AllowMultiple=false)>]
type XmlArrayAttribute = class
    inherit Attribute
type XmlArrayAttribute = class
    inherit Attribute
[<System.AttributeUsage(System.AttributeTargets.Field | System.AttributeTargets.Parameter | System.AttributeTargets.Property | System.AttributeTargets.ReturnValue)>]
type XmlArrayAttribute = class
    inherit Attribute
Public Class XmlArrayAttribute
Inherits Attribute
Dědičnost
XmlArrayAttribute
Atributy

Příklady

Následující příklad serializace instance třídy do dokumentu XML, který obsahuje několik polí objektů.The following example serializes a class instance into an XML document that contains several object arrays. XmlArrayAttributeJe použita na členy, kteří se stanou poli XML elementů.The XmlArrayAttribute is applied to the members that become XML element arrays.

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

using namespace System;
using namespace System::IO;
using namespace System::Xml::Serialization;
using namespace System::Xml;
public ref class Item
{
public:

   [XmlElement(ElementName="OrderItem")]
   String^ ItemName;
   String^ ItemCode;
   Decimal ItemPrice;
   int ItemQuantity;
};

public ref class BookItem: public Item
{
public:
   String^ Title;
   String^ Author;
   String^ ISBN;
};

// This is the class that will be serialized.
public ref class MyRootClass
{
private:
   array<Item^>^items;

public:

   /* Here is a simple way to serialize the array as XML. Using the
         XmlArrayAttribute, assign an element name and namespace. The
         IsNullable property determines whether the element will be 
         generated if the field is set to a null value. If set to true,
         the default, setting it to a null value will cause the XML
         xsi:null attribute to be generated. */

   [XmlArray(ElementName="MyStrings",
   Namespace="http://www.cpandl.com",IsNullable=true)]
   array<String^>^MyStringArray;

   /* Here is a more complex example of applying an 
         XmlArrayAttribute. The Items property can contain both Item 
         and BookItem objects. Use the XmlArrayItemAttribute to specify
         that both types can be inserted into the array. */
   [XmlArrayItem(ElementName="Item",
   IsNullable=true,
   Type=Item::typeid,
   Namespace="http://www.cpandl.com"),
   XmlArrayItem(ElementName="BookItem",
   IsNullable=true,
   Type=BookItem::typeid,
   Namespace="http://www.cohowinery.com")]
   [XmlArray]
   property array<Item^>^ Items 
   {
      array<Item^>^ get()
      {
         return items;
      }

      void set( array<Item^>^value )
      {
         items = value;
      }
   }
};

public ref class Run
{
public:
   void SerializeDocument( String^ filename )
   {
      // Creates a new XmlSerializer.
      XmlSerializer^ s = gcnew XmlSerializer( MyRootClass::typeid );

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

      // Creates an instance of the class to serialize. 
      MyRootClass^ myRootClass = gcnew MyRootClass;

      /* Uses a basic method of creating an XML array: Create and 
            populate a string array, and assign it to the 
            MyStringArray property. */
      array<String^>^myString = {"Hello","world","!"};
      myRootClass->MyStringArray = myString;

      /* Uses a more advanced method of creating an array:
               create instances of the Item and BookItem, where BookItem 
               is derived from Item. */
      Item^ item1 = gcnew Item;
      BookItem^ item2 = gcnew BookItem;

      // Sets the objects' properties.
      item1->ItemName = "Widget1";
      item1->ItemCode = "w1";
      item1->ItemPrice = 231;
      item1->ItemQuantity = 3;
      item2->ItemCode = "w2";
      item2->ItemPrice = 123;
      item2->ItemQuantity = 7;
      item2->ISBN = "34982333";
      item2->Title = "Book of Widgets";
      item2->Author = "John Smith";

      // Fills the array with the items.
      array<Item^>^myItems = {item1,item2};

      // Sets the class's Items property to the array.
      myRootClass->Items = myItems;

      /* Serializes the class, writes it to disk, and closes 
               the TextWriter. */
      s->Serialize( myWriter, myRootClass );
      myWriter->Close();
   }
};

int main()
{
   Run^ test = gcnew Run;
   test->SerializeDocument( "books.xml" );
}
using System;
using System.IO;
using System.Xml.Serialization;
using System.Xml;

public class Run
{
   public static void Main()
   {
      Run test = new Run();
      test.SerializeDocument("books.xml");
   }

   public void SerializeDocument(string filename)
   {
      // Creates a new XmlSerializer.
      XmlSerializer s =
      new XmlSerializer(typeof(MyRootClass));

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

      // Creates an instance of the class to serialize.
      MyRootClass myRootClass = new MyRootClass();

      /* Uses a basic method of creating an XML array: Create and
      populate a string array, and assign it to the
      MyStringArray property. */

      string [] myString = {"Hello", "world", "!"};
      myRootClass.MyStringArray = myString;

      /* Uses a more advanced method of creating an array:
         create instances of the Item and BookItem, where BookItem
         is derived from Item. */
      Item item1 = new Item();
      BookItem item2 = new BookItem();

      // Sets the objects' properties.
      item1.ItemName = "Widget1";
      item1.ItemCode = "w1";
      item1.ItemPrice = 231;
      item1.ItemQuantity = 3;

      item2.ItemCode = "w2";
      item2.ItemPrice = 123;
      item2.ItemQuantity = 7;
      item2.ISBN = "34982333";
      item2.Title = "Book of Widgets";
      item2.Author = "John Smith";

      // Fills the array with the items.
      Item [] myItems = {item1,item2};

      // Sets the class's Items property to the array.
      myRootClass.Items = myItems;

      /* Serializes the class, writes it to disk, and closes
         the TextWriter. */
      s.Serialize(myWriter, myRootClass);
      myWriter.Close();
   }
}

// This is the class that will be serialized.
public class MyRootClass
{
   private Item [] items;

   /* Here is a simple way to serialize the array as XML. Using the
      XmlArrayAttribute, assign an element name and namespace. The
      IsNullable property determines whether the element will be
      generated if the field is set to a null value. If set to true,
      the default, setting it to a null value will cause the XML
      xsi:null attribute to be generated. */
   [XmlArray(ElementName = "MyStrings",
   Namespace = "http://www.cpandl.com", IsNullable = true)]
   public string[] MyStringArray;

   /* Here is a more complex example of applying an
      XmlArrayAttribute. The Items property can contain both Item
      and BookItem objects. Use the XmlArrayItemAttribute to specify
      that both types can be inserted into the array. */
   [XmlArrayItem(ElementName= "Item",
   IsNullable=true,
   Type = typeof(Item),
   Namespace = "http://www.cpandl.com"),
   XmlArrayItem(ElementName = "BookItem",
   IsNullable = true,
   Type = typeof(BookItem),
   Namespace = "http://www.cohowinery.com")]
   [XmlArray]
   public Item []Items
   {
      get{return items;}
      set{items = value;}
   }
}

public class Item{
   [XmlElement(ElementName = "OrderItem")]
   public string ItemName;
   public string ItemCode;
   public decimal ItemPrice;
   public int ItemQuantity;
}

public class BookItem:Item
{
   public string Title;
   public string Author;
   public string ISBN;
}

Option Explicit
Option Strict

Imports System.IO
Imports System.Xml.Serialization
Imports System.Xml


Public Class Run
    
    Public Shared Sub Main()
        Dim test As New Run()
        test.SerializeDocument("books.xml")
    End Sub
    
    
    Public Sub SerializeDocument(ByVal filename As String)
        ' Creates a new XmlSerializer.
        Dim s As New XmlSerializer(GetType(MyRootClass))
        
        ' Writing the file requires a StreamWriter.
        Dim myWriter As New StreamWriter(filename)
        
        ' Creates an instance of the class to serialize. 
        Dim myRootClass As New MyRootClass()
        
        ' Uses a basic method of creating an XML array: Create and
        ' populate a string array, and assign it to the
        ' MyStringArray property. 
        
        Dim myString() As String =  {"Hello", "world", "!"}
        myRootClass.MyStringArray = myString
        
        ' Uses a more advanced method of creating an array:
        ' create instances of the Item and BookItem, where BookItem
        ' is derived from Item. 
        Dim item1 As New Item()
        Dim item2 As New BookItem()
        
        ' Sets the objects' properties.
        With item1
            .ItemName = "Widget1"
            .ItemCode = "w1"
            .ItemPrice = 231
            .ItemQuantity = 3
        End With

        With item2
            .ItemCode = "w2"
            .ItemPrice = 123
            .ItemQuantity = 7
            .ISBN = "34982333"
            .Title = "Book of Widgets"
            .Author = "John Smith"
        End With
        
        ' Fills the array with the items.
        Dim myItems() As Item =  {item1, item2}
        
        ' Set class's Items property to the array.
        myRootClass.Items = myItems
        
        ' Serializes the class, writes it to disk, and closes
        ' the TextWriter. 
        s.Serialize(myWriter, myRootClass)
        myWriter.Close()
    End Sub
End Class


' This is the class that will be serialized.
Public Class MyRootClass
    Private myItems() As Item
    
    ' Here is a simple way to serialize the array as XML. Using the
    ' XmlArrayAttribute, assign an element name and namespace. The
    ' IsNullable property determines whether the element will be
    ' generated if the field is set to a null value. If set to true,
    ' the default, setting it to a null value will cause the XML
    ' xsi:null attribute to be generated.
    <XmlArray(ElementName := "MyStrings", _
         Namespace := "http://www.cpandl.com", _
         IsNullable := True)> _
    Public MyStringArray() As String
    
    ' Here is a more complex example of applying an
    ' XmlArrayAttribute. The Items property can contain both Item
    ' and BookItem objects. Use the XmlArrayItemAttribute to specify
    ' that both types can be inserted into the array.
    <XmlArrayItem(ElementName := "Item", _
        IsNullable := True, _
        Type := GetType(Item), _
        Namespace := "http://www.cpandl.com"), _
     XmlArrayItem(ElementName := "BookItem", _
        IsNullable := True, _
        Type := GetType(BookItem), _
        Namespace := "http://www.cohowinery.com"), _
     XmlArray()> _
    Public Property Items As Item()
        Get
            Return myItems
        End Get
        Set
            myItems = value
        End Set
    End Property
End Class
 
Public Class Item
    <XmlElement(ElementName := "OrderItem")> _
    Public ItemName As String
    Public ItemCode As String
    Public ItemPrice As Decimal
    Public ItemQuantity As Integer
End Class

Public Class BookItem
    Inherits Item
    Public Title As String
    Public Author As String
    Public ISBN As String
End Class

Poznámky

XmlArrayAttributePatří do rodiny atributů, které řídí, jak XmlSerializer serializace nebo deserializace objektu.The XmlArrayAttribute belongs to a family of attributes that controls how the XmlSerializer serializes or deserializes an object. Úplný seznam podobných atributů naleznete v tématu atributy, které řídí serializaci XML.For a complete list of similar attributes, see Attributes That Control XML Serialization.

Můžete použít XmlArrayAttribute pro veřejné pole nebo vlastnost pro čtení a zápis, která vrací pole objektů.You can apply the XmlArrayAttribute to a public field or read/write property that returns an array of objects. Můžete ji také použít na kolekce a pole, která vracejí ArrayList nebo jakékoli pole, které vrací objekt, který implementuje IEnumerable rozhraní.You can also apply it to collections and fields that return an ArrayList or any field that returns an object that implements the IEnumerable interface.

Použijete-li XmlArrayAttribute pro člena třídy, Serialize Metoda XmlSerializer třídy vygeneruje vnořenou sekvenci prvků XML od daného člena.When you apply the XmlArrayAttribute to a class member, the Serialize method of the XmlSerializer class generates a nested sequence of XML elements from that member. Dokument schématu XML (soubor. XSD) označuje takové pole jako complexType .An XML schema document (an .xsd file), indicates such an array as a complexType. Například pokud třída, která má být serializován, představuje nákupní objednávku, můžete vygenerovat pole koupených položek pomocí XmlArrayAttribute funkce na veřejné pole, které vrací pole objektů reprezentujících položky objednávky.For example, if the class to be serialized represents a purchase order, you can generate an array of purchased items by applying the XmlArrayAttribute to a public field that returns an array of objects that represent order items.

Pokud nejsou aplikovány žádné atributy na veřejné pole nebo vlastnost, která vrací pole komplexních nebo primitivních objektů typu, XmlSerializer vygeneruje ve výchozím nastavení vnořenou sekvenci prvků XML.If no attributes are applied to a public field or property that returns an array of complex or primitive type objects, the XmlSerializer generates a nested sequence of XML elements by default. Pro přesnější kontrolu nad tím, jaké prvky XML jsou generovány, použijte XmlArrayItemAttribute a XmlArrayAttribute na pole nebo vlastnost.To more precisely control what XML elements are generated, apply an XmlArrayItemAttribute and an XmlArrayAttribute to the field or property. Například ve výchozím nastavení je název generovaného elementu XML odvozen z identifikátoru členu. můžete změnit název generovaného elementu XML nastavením ElementName Vlastnosti.For example, by default, the name of the generated XML element is derived from the member identifier You can change the name of the generated XML element by setting the ElementName property.

Při serializaci pole, které obsahuje položky konkrétního typu a všech tříd odvozených z tohoto typu, je nutné použít XmlArrayItemAttribute k deklaraci každého typu.If you serialize an array that contains items of a specific type and all the classes derived from that type, you must use the XmlArrayItemAttribute to declare each of the types.

Poznámka

Můžete použít XmlArray ve svém kódu místo delší XmlArrayAttribute .You can use XmlArray in your code instead of the longer XmlArrayAttribute.

Další informace o použití atributů naleznete v tématu Attributes.For more information about using attributes, see Attributes.

Konstruktory

XmlArrayAttribute()

Inicializuje novou instanci XmlArrayAttribute třídy.Initializes a new instance of the XmlArrayAttribute class.

XmlArrayAttribute(String)

Inicializuje novou instanci XmlArrayAttribute třídy a určí název elementu XML generovaný v instanci dokumentu XML.Initializes a new instance of the XmlArrayAttribute class and specifies the XML element name generated in the XML document instance.

Vlastnosti

ElementName

Získá nebo nastaví název elementu XML, který je dán serializovanému poli.Gets or sets the XML element name given to the serialized array.

Form

Získává nebo nastavuje hodnotu, která indikuje, jestli název elementu XML, který vygenerovala, XmlSerializer je kvalifikovaný nebo nekvalifikovaný.Gets or sets a value that indicates whether the XML element name generated by the XmlSerializer is qualified or unqualified.

IsNullable

Získává nebo nastavuje hodnotu, která indikuje, jestli XmlSerializer musí člen serializovat jako prázdnou značku XML s xsi:nil atributem nastaveným na true .Gets or sets a value that indicates whether the XmlSerializer must serialize a member as an empty XML tag with the xsi:nil attribute set to true.

Namespace

Získá nebo nastaví obor názvů elementu XML.Gets or sets the namespace of the XML element.

Order

Získá nebo nastaví explicitní pořadí, ve kterém jsou elementy serializovány nebo deserializovány.Gets or sets the explicit order in which the elements are serialized or deserialized.

TypeId

Při implementaci v odvozené třídě získá jedinečný identifikátor Attribute .When implemented in a derived class, gets a unique identifier for this Attribute.

(Zděděno od Attribute)

Metody

Equals(Object)

Vrací hodnotu, která určuje, zda je tato instance rovna zadanému objektu.Returns a value that indicates whether this instance is equal to a specified object.

(Zděděno od Attribute)
GetHashCode()

Vrátí hodnotu hash pro tuto instanci.Returns the hash code for this instance.

(Zděděno od Attribute)
GetType()

Získá Type aktuální instanci.Gets the Type of the current instance.

(Zděděno od Object)
IsDefaultAttribute()

Při přepsání v odvozené třídě označuje, zda je hodnota této instance výchozí hodnotou pro odvozenou třídu.When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class.

(Zděděno od Attribute)
Match(Object)

Při přepsání v odvozené třídě vrátí hodnotu, která označuje, zda je tato instance rovna zadanému objektu.When overridden in a derived class, returns a value that indicates whether this instance equals a specified object.

(Zděděno od Attribute)
MemberwiseClone()

Vytvoří kopii aktuálního seznamu Object .Creates a shallow copy of the current Object.

(Zděděno od Object)
ToString()

Vrátí řetězec, který představuje aktuální objekt.Returns a string that represents the current object.

(Zděděno od Object)

Explicitní implementace rozhraní

_Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr)

Mapuje sadu názvů na odpovídající sadu identifikátorů pro rozesílání.Maps a set of names to a corresponding set of dispatch identifiers.

(Zděděno od Attribute)
_Attribute.GetTypeInfo(UInt32, UInt32, IntPtr)

Načte informace o typu pro objekt, který lze použít k získání informací o typu pro rozhraní.Retrieves the type information for an object, which can be used to get the type information for an interface.

(Zděděno od Attribute)
_Attribute.GetTypeInfoCount(UInt32)

Získá počet rozhraní typu informací, které objekt poskytuje (0 nebo 1).Retrieves the number of type information interfaces that an object provides (either 0 or 1).

(Zděděno od Attribute)
_Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr)

Poskytuje přístup k vlastnostem a metodám vystaveným objektem.Provides access to properties and methods exposed by an object.

(Zděděno od Attribute)

Platí pro

Viz také