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XmlSerializer Constructor (Type, XmlAttributeOverrides, array<Type>, XmlRootAttribute, String)

Initializes a new instance of the XmlSerializer class that can serialize objects of type Object into XML document instances, and deserialize XML document instances into objects of type Object. Each object to be serialized can itself contain instances of classes, which this overload overrides with other classes. This overload also specifies the default namespace for all the XML elements and the class to use as the XML root element.

Namespace:  System.Xml.Serialization
Assembly:  System.Xml (in System.Xml.dll)

public:
XmlSerializer(
	Type^ type, 
	XmlAttributeOverrides^ overrides, 
	array<Type^>^ extraTypes, 
	XmlRootAttribute^ root, 
	String^ defaultNamespace
)

Parameters

type
Type: System::Type

The type of the object that this XmlSerializer can serialize.

overrides
Type: System.Xml.Serialization::XmlAttributeOverrides

An XmlAttributeOverrides that extends or overrides the behavior of the class specified in the type parameter.

extraTypes
Type: array<System::Type>

A Type array of additional object types to serialize.

root
Type: System.Xml.Serialization::XmlRootAttribute

An XmlRootAttribute that defines the XML root element properties.

defaultNamespace
Type: System::String

The default namespace of all XML elements in the XML document.

The overrides parameter allows for the creation of an XmlSerializer that serializes a class that extends or overrides the behavior of a base class. For example, given a DLL, it is possible to create a class that inherits or extends a class contained in the DLL. To serialize such a class, you must use an instance of the XmlAttributeOverrides class when constructing the XmlSerializer. For more details, see XmlAttributeOverrides.

By default, if a public property or field returns an object, or array of objects, the object types are automatically serialized. However, if a class contains a field or property that returns an array of type Object, any object can be inserted into that array. In that case, the XmlSerializer must be instructed to expect all the possible object types that are inserted into the Object array. To do this, use the extraTypes parameter to specify the extra object types to serialize or deserialize.

The root element of an XML document encloses all the other elements. By default, the object specified by the type parameter is serialized as the root element. Properties, such as the XML element name of the root element are taken from the type object. However, the root parameter allows you to replace the default object's information by specifying an XmlRootAttribute; the object allows you to set a different namespace, element name, and so on.

Use the defaultName parameter to specify the default namespace of all XML elements generated by the XmlSerializer.

The following example serializes an instance of a class that is defined in a DLL and to do so, overrides the public members found in the class. The example also specifies an array of extra types, the default namespace for all XML elements, and the class to use that provides the XML root element information. The example assumes that the code at the beginning has been compiled into a DLL named HighSchool.

// Beginning of the HighSchool.dll 
#using <System.Xml.dll>
#using <System.dll>

using namespace System;
using namespace System::IO;
using namespace System::Xml;
using namespace System::Xml::Serialization;

namespace HighSchool
{
   public ref class Student
   {
   public:
      String^ Name;
      int ID;
   };

   public ref class MyClass
   {
   public:
      array<Student^>^Students;
   };
}

namespace College
{

using namespace HighSchool;
   public ref class Graduate: public HighSchool::Student
   {
   public:
      Graduate(){}

      // Add a new field named University.
      String^ University;

      // Use extra types to use this field. 
      array<Object^>^Info;
   };

   public ref class Address
   {
   public:
      String^ City;
   };

   public ref class Phone
   {
   public:
      String^ Number;
   };

   public ref class Run
   {
   public:
      static void main()
      {
         Run^ test = gcnew Run;
         test->WriteOverriddenAttributes( "College.xml" );
         test->ReadOverriddenAttributes( "College.xml" );
      }

   private:
      void WriteOverriddenAttributes( String^ filename )
      {
         // Writing the file requires a TextWriter.
         TextWriter^ myStreamWriter = gcnew StreamWriter( filename );

         // Create an XMLAttributeOverrides class.
         XmlAttributeOverrides^ attrOverrides = gcnew XmlAttributeOverrides;

         // Create the XmlAttributes class.
         XmlAttributes^ attrs = gcnew XmlAttributes;

         /* Override the Student class. "Alumni" is the name
               of the overriding element in the XML output. */
         XmlElementAttribute^ attr = gcnew XmlElementAttribute( "Alumni",Graduate::typeid );

         /* Add the XmlElementAttribute to the collection of
               elements in the XmlAttributes object. */
         attrs->XmlElements->Add( attr );

         /* Add the XmlAttributes to the XmlAttributeOverrides. 
               "Students" is the name being overridden. */
         attrOverrides->Add( HighSchool::MyClass::typeid, "Students", attrs );

         // Create array of extra types. 
         array<Type^>^extraTypes = gcnew array<Type^>(2);
         extraTypes[ 0 ] = Address::typeid;
         extraTypes[ 1 ] = Phone::typeid;

         // Create an XmlRootAttribute.
         XmlRootAttribute^ root = gcnew XmlRootAttribute( "Graduates" );

         /* Create the XmlSerializer with the 
               XmlAttributeOverrides object. */
         XmlSerializer^ mySerializer = gcnew XmlSerializer( HighSchool::MyClass::typeid,attrOverrides,extraTypes,root,"http://www.microsoft.com" );
         MyClass ^ myClass = gcnew MyClass;
         Graduate^ g1 = gcnew Graduate;
         g1->Name = "Jacki";
         g1->ID = 1;
         g1->University = "Alma";
         Graduate^ g2 = gcnew Graduate;
         g2->Name = "Megan";
         g2->ID = 2;
         g2->University = "CM";
         array<Student^>^myArray = {g1,g2};
         myClass->Students = myArray;

         // Create extra information.
         Address^ a1 = gcnew Address;
         a1->City = "Ionia";
         Address^ a2 = gcnew Address;
         a2->City = "Stamford";
         Phone^ p1 = gcnew Phone;
         p1->Number = "555-0101";
         Phone^ p2 = gcnew Phone;
         p2->Number = "555-0100";
         array<Object^>^o1 = {a1,p1};
         array<Object^>^o2 = {a2,p2};
         g1->Info = o1;
         g2->Info = o2;
         mySerializer->Serialize( myStreamWriter, myClass );
         myStreamWriter->Close();
      }

      void ReadOverriddenAttributes( String^ filename )
      {
         /* The majority of the code here is the same as that in the
               WriteOverriddenAttributes method. Because the XML being read
               doesn't conform to the schema defined by the DLL, the
               XMLAttributesOverrides must be used to create an 
               XmlSerializer instance to read the XML document.*/
         XmlAttributeOverrides^ attrOverrides = gcnew XmlAttributeOverrides;
         XmlAttributes^ attrs = gcnew XmlAttributes;
         XmlElementAttribute^ attr = gcnew XmlElementAttribute( "Alumni",Graduate::typeid );
         attrs->XmlElements->Add( attr );
         attrOverrides->Add( HighSchool::MyClass::typeid, "Students", attrs );
         array<Type^>^extraTypes = gcnew array<Type^>(2);
         extraTypes[ 0 ] = Address::typeid;
         extraTypes[ 1 ] = Phone::typeid;
         XmlRootAttribute^ root = gcnew XmlRootAttribute( "Graduates" );
         XmlSerializer^ readSerializer = gcnew XmlSerializer( HighSchool::MyClass::typeid,attrOverrides,extraTypes,root,"http://www.microsoft.com" );

         // A FileStream object is required to read the file. 
         FileStream^ fs = gcnew FileStream( filename,FileMode::Open );
         MyClass ^ myClass;
         myClass = dynamic_cast<MyClass^>(readSerializer->Deserialize( fs ));

         /* Here is the difference between reading and writing an 
               XML document: You must declare an object of the derived 
               type (Graduate) and cast the Student instance to it.*/
         Graduate^ g;
         Address^ a;
         Phone^ p;
         System::Collections::IEnumerator^ myEnum = myClass->Students->GetEnumerator();
         while ( myEnum->MoveNext() )
         {
            Graduate^ grad = safe_cast<Graduate^>(myEnum->Current);
            g = dynamic_cast<Graduate^>(grad);
            Console::Write( "{0}\t", g->Name );
            Console::Write( "{0}\t", g->ID );
            Console::Write( "{0}\n", g->University );
            a = dynamic_cast<Address^>(g->Info[ 0 ]);
            Console::WriteLine( a->City );
            p = dynamic_cast<Phone^>(g->Info[ 1 ]);
            Console::WriteLine( p->Number );
         }
      }
   };
}

int main()
{
   College::Run::main();
}

.NET Framework

Supported in: 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Store apps

Supported in: Windows 8

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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