XmlArrayItemAttribute クラス
アセンブリ: System.Xml (system.xml.dll 内)
構文
<AttributeUsageAttribute(AttributeTargets.Property Or AttributeTargets.Field Or AttributeTargets.Parameter Or AttributeTargets.ReturnValue, AllowMultiple:=True)> _ Public Class XmlArrayItemAttribute Inherits Attribute
[AttributeUsageAttribute(AttributeTargets.Property|AttributeTargets.Field|AttributeTargets.Parameter|AttributeTargets.ReturnValue, AllowMultiple=true)] public class XmlArrayItemAttribute : Attribute
[AttributeUsageAttribute(AttributeTargets::Property|AttributeTargets::Field|AttributeTargets::Parameter|AttributeTargets::ReturnValue, AllowMultiple=true)] public ref class XmlArrayItemAttribute : public Attribute
XmlArrayItemAttribute は、XmlSerializer がオブジェクトをシリアル化または逆シリアル化する方法を制御する一連の属性の 1 つです。類似する属性の完全な一覧については、「XML シリアル化を制御する属性」を参照してください。
XmlArrayItemAttribute は、配列を返したり配列へのアクセスを提供したりする任意のパブリックな読み取り/書き込みメンバに適用できます。たとえば、オブジェクトの配列を返すフィールド、コレクション、ArrayList、または IEnumerable インターフェイスを実装する任意のクラスがこれに該当します。
XmlArrayItemAttribute はポリモーフィズムをサポートしています。つまり XmlSerializer によって派生オブジェクトを配列に追加できます。たとえば、Animal という基本クラスから派生した Mammal クラスがあるとします。また、MyAnimals というクラスには Animal オブジェクトの配列を返すフィールドがあるとします。XmlSerializer により Animal 型および Mammal 型の両方をシリアル化するには、使用可能な 2 つの型のいずれか一方を指定して、フィールドに XmlArrayItemAttribute を 2 回適用します。
メモ |
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XmlArrayItemAttribute または XmlElementAttribute の複数のインスタンスを適用して、配列に挿入できるオブジェクトの型を指定できます。 |
Employee オブジェクトの配列を返す Employees というフィールドがある Group というクラスをシリアル化する例を次に示します。この例では XmlArrayItemAttribute をフィールドに適用します。これにより、XmlSerializer に対して、基本クラス (Employee) 型と派生クラス (Manager) 型の両方のオブジェクトをシリアル化された配列に挿入するように指示します。
Option Explicit Option Strict Imports System Imports System.IO Imports System.Xml.Serialization Imports Microsoft.VisualBasic Public Class Group ' The XmlArrayItemAttribute allows the XmlSerializer to insert ' both the base type (Employee) and derived type (Manager) ' into serialized arrays. <XmlArrayItem(GetType(Manager)), _ XmlArrayItem(GetType(Employee))> _ Public Employees() As Employee ' Use the XmlArrayItemAttribute to specify types allowed ' in an array of Object items. <XmlArray(), _ XmlArrayItem(GetType(Integer), ElementName := "MyNumber"), _ XmlArrayItem(GetType(String), ElementName := "MyString"), _ XmlArrayItem(GetType(Manager))> _ Public ExtraInfo() As Object End Class Public Class Employee Public Name As String End Class Public Class Manager Inherits Employee Public Level As Integer End Class Public Class Run Public Shared Sub Main() Dim test As New Run() test.SerializeObject("TypeDoc.xml") test.DeserializeObject("TypeDoc.xml") End Sub Public Sub SerializeObject(ByVal filename As String) ' Creates a new XmlSerializer. Dim s As New XmlSerializer(GetType(Group)) ' Writing the XML file to disk requires a TextWriter. Dim writer As New StreamWriter(filename) Dim group As New Group() Dim manager As New Manager() Dim emp1 As New Employee() Dim emp2 As New Employee() manager.Name = "Consuela" manager.Level = 3 emp1.Name = "Seiko" emp2.Name = "Martina" Dim emps() As Employee = {manager, emp1, emp2} group.Employees = emps ' Creates an int and a string and assigns to ExtraInfo. group.ExtraInfo = New Object() {43, "Extra", manager} ' Serializes the object, and closes the StreamWriter. s.Serialize(writer, group) writer.Close() End Sub Public Sub DeserializeObject(ByVal filename As String) Dim fs As New FileStream(filename, FileMode.Open) Dim x As New XmlSerializer(GetType(Group)) Dim g As Group = CType(x.Deserialize(fs), Group) Console.WriteLine("Members:") Dim e As Employee For Each e In g.Employees Console.WriteLine(ControlChars.Tab & e.Name) Next e End Sub End Class
using System; using System.IO; using System.Xml.Serialization; public class Group { /* The XmlArrayItemAttribute allows the XmlSerializer to insert both the base type (Employee) and derived type (Manager) into serialized arrays. */ [XmlArrayItem(typeof(Manager)), XmlArrayItem(typeof(Employee))] public Employee[] Employees; /* Use the XmlArrayItemAttribute to specify types allowed in an array of Object items. */ [XmlArray] [XmlArrayItem (typeof(int), ElementName = "MyNumber"), XmlArrayItem (typeof(string), ElementName = "MyString"), XmlArrayItem(typeof(Manager))] public object [] ExtraInfo; } public class Employee { public string Name; } public class Manager:Employee{ public int Level; } public class Run { public static void Main() { Run test = new Run(); test.SerializeObject("TypeDoc.xml"); test.DeserializeObject("TypeDoc.xml"); } public void SerializeObject(string filename) { // Creates a new XmlSerializer. XmlSerializer s = new XmlSerializer(typeof(Group)); // Writing the XML file to disk requires a TextWriter. TextWriter writer = new StreamWriter(filename); Group group = new Group(); Manager manager = new Manager(); Employee emp1 = new Employee(); Employee emp2 = new Employee(); manager.Name = "Consuela"; manager.Level = 3; emp1.Name = "Seiko"; emp2.Name = "Martina"; Employee [] emps = new Employee[3]{manager, emp1, emp2}; group.Employees = emps; // Creates an int and a string and assigns to ExtraInfo. group.ExtraInfo = new Object[3]{43, "Extra", manager}; // Serializes the object, and closes the StreamWriter. s.Serialize(writer, group); writer.Close(); } public void DeserializeObject(string filename) { FileStream fs = new FileStream(filename, FileMode.Open); XmlSerializer x = new XmlSerializer(typeof(Group)); Group g = (Group) x.Deserialize(fs); Console.WriteLine("Members:"); foreach(Employee e in g.Employees) { Console.WriteLine("\t" + e.Name); } } }
#using <System.Xml.dll> #using <System.dll> using namespace System; using namespace System::IO; using namespace System::Xml::Serialization; public ref class Employee { public: String^ Name; }; public ref class Manager: public Employee { public: int Level; }; public ref class Group { public: /* The XmlArrayItemAttribute allows the XmlSerializer to insert both the base type (Employee) and derived type (Manager) into serialized arrays. */ [XmlArrayItem(Manager::typeid), XmlArrayItem(Employee::typeid)] array<Employee^>^Employees; /* Use the XmlArrayItemAttribute to specify types allowed in an array of Object items. */ [XmlArray] [XmlArrayItem(Int32::typeid, ElementName="MyNumber"), XmlArrayItem(String::typeid, ElementName="MyString"), XmlArrayItem(Manager::typeid)] array<Object^>^ExtraInfo; }; void SerializeObject( String^ filename ) { // Creates a new XmlSerializer. XmlSerializer^ s = gcnew XmlSerializer( Group::typeid ); // Writing the XML file to disk requires a TextWriter. TextWriter^ writer = gcnew StreamWriter( filename ); Group^ group = gcnew Group; Manager^ manager = gcnew Manager; Employee^ emp1 = gcnew Employee; Employee^ emp2 = gcnew Employee; manager->Name = "Consuela"; manager->Level = 3; emp1->Name = "Seiko"; emp2->Name = "Martina"; array<Employee^>^emps = {manager,emp1,emp2}; group->Employees = emps; // Creates an int and a string and assigns to ExtraInfo. array<Object^>^temp = {43,"Extra",manager}; group->ExtraInfo = temp; // Serializes the object, and closes the StreamWriter. s->Serialize( writer, group ); writer->Close(); } void DeserializeObject( String^ filename ) { FileStream^ fs = gcnew FileStream( filename,FileMode::Open ); XmlSerializer^ x = gcnew XmlSerializer( Group::typeid ); Group^ g = dynamic_cast<Group^>(x->Deserialize( fs )); Console::WriteLine( "Members:" ); System::Collections::IEnumerator^ myEnum = g->Employees->GetEnumerator(); while ( myEnum->MoveNext() ) { Employee^ e = safe_cast<Employee^>(myEnum->Current); Console::WriteLine( "\t{0}", e->Name ); } } int main() { SerializeObject( "TypeDoc.xml" ); DeserializeObject( "TypeDoc.xml" ); }
import System.*; import System.IO.*; import System.Xml.Serialization.*; public class Group { /* The XmlArrayItemAttribute allows the XmlSerializer to insert both the base type (Employee) and derived type (Manager) into serialized arrays. */ /** @attribute XmlArrayItem(Manager.class) @attribute XmlArrayItem(Employee.class) */ public Employee employees[]; /* Use the XmlArrayItemAttribute to specify types allowed in an array of Object items. */ /** @attribute XmlArray() */ /** @attribute XmlArrayItem(int.class, ElementName = "MyNumber") @attribute XmlArrayItem(String.class, ElementName = "MyString") @attribute XmlArrayItem(Manager.class) */ public Object extraInfo[]; } //Group public class Employee { public String name; } //Employee public class Manager extends Employee { public int level; } //Manager public class Run { public static void main(String[] args) { Run test = new Run(); test.SerializeObject("TypeDoc.xml"); test.DeserializeObject("TypeDoc.xml"); } //main public void SerializeObject(String fileName) { // Creates a new XmlSerializer. XmlSerializer s = new XmlSerializer(Group.class.ToType()); // Writing the XML file to disk requires a TextWriter. TextWriter writer = new StreamWriter(fileName); Group group = new Group(); Manager manager = new Manager(); Employee emp1 = new Employee(); Employee emp2 = new Employee(); manager.name = "Consuela"; manager.level = 3; emp1.name = "Seiko"; emp2.name = "Martina"; Employee emps[] = new Employee[] { manager, emp1, emp2 }; group.employees = emps; // Creates an int and a string and assigns to ExtraInfo. group.extraInfo = new Object[] { (Int32)43, "Extra", manager }; // Serializes the object, and closes the StreamWriter. s.Serialize(writer, group); writer.Close(); } //SerializeObject public void DeserializeObject(String fileName) { FileStream fs = new FileStream(fileName, FileMode.Open); XmlSerializer x = new XmlSerializer(Group.class.ToType()); Group g = (Group)(x.Deserialize(fs)); Console.WriteLine("Members:"); for (int iCtr = 0; iCtr < g.employees.length; iCtr++) { Employee e = (Employee)g.employees.get_Item(iCtr); Console.WriteLine("\t" + e.name); } } //DeserializeObject } //Run
System.Attribute
System.Xml.Serialization.XmlArrayItemAttribute
プラットフォーム
Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
開発プラットフォームの中には、.NET Framework によってサポートされていないバージョンがあります。サポートされているバージョンについては、「システム要件」を参照してください。
参照
- XmlArrayItemAttribute クラスのページへのリンク