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XmlSerializer Class

Serializes and deserializes objects into and from XML documents. The XmlSerializer enables you to control how objects are encoded into XML.

System.Object
  System.Xml.Serialization.XmlSerializer

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

type XmlSerializer =  class end

The XmlSerializer type exposes the following members.

  NameDescription
Protected methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsXmlSerializer()Infrastructure. Initializes a new instance of the XmlSerializer class.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsXmlSerializer(Type)Initializes a new instance of the XmlSerializer class that can serialize objects of the specified type into XML documents, and deserialize XML documents into objects of the specified type.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryXmlSerializer(XmlTypeMapping)Initializes an instance of the XmlSerializer class using an object that maps one type to another.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsXmlSerializer(Type, String)Initializes a new instance of the XmlSerializer class that can serialize objects of the specified type into XML documents, and deserialize XML documents into objects of the specified type. Specifies the default namespace for all the XML elements.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsXmlSerializer(Type, Type[])Initializes a new instance of the XmlSerializer class that can serialize objects of the specified type into XML documents, and deserialize XML documents into object of a specified type. If a property or field returns an array, the extraTypes parameter specifies objects that can be inserted into the array.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsXmlSerializer(Type, XmlAttributeOverrides)Initializes a new instance of the XmlSerializer class that can serialize objects of the specified type into XML documents, and deserialize XML documents into objects of the specified type. Each object to be serialized can itself contain instances of classes, which this overload can override with other classes.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsXmlSerializer(Type, XmlRootAttribute)Initializes a new instance of the XmlSerializer class that can serialize objects of the specified type into XML documents, and deserialize an XML document into object of the specified type. It also specifies the class to use as the XML root element.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsXmlSerializer(Type, XmlAttributeOverrides, 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.
Public methodXmlSerializer(Type, XmlAttributeOverrides, Type[], XmlRootAttribute, String, 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.
Public methodXmlSerializer(Type, XmlAttributeOverrides, Type[], XmlRootAttribute, String, String, Evidence)Infrastructure. Obsolete. Initializes a new instance of the XmlSerializer class that can serialize objects of the specified type into XML document instances, and deserialize XML document instances into objects of the specified type. This overload allows you to supply other types that can be encountered during a serialization or deserialization operation, as well as a default namespace for all XML elements, the class to use as the XML root element, its location, and credentials required for access.
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  NameDescription
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsCanDeserializeGets a value that indicates whether this XmlSerializer can deserialize a specified XML document.
Protected methodCreateReaderInfrastructure. Returns an object used to read the XML document to be serialized.
Protected methodCreateWriterInfrastructure. When overridden in a derived class, returns a writer used to serialize the object.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsDeserialize(Stream)Deserializes the XML document contained by the specified Stream.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsDeserialize(TextReader)Deserializes the XML document contained by the specified TextReader.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsDeserialize(XmlReader)Deserializes the XML document contained by the specified XmlReader.
Protected methodDeserialize(XmlSerializationReader)Infrastructure. Deserializes the XML document contained by the specified XmlSerializationReader.
Public methodSupported by the XNA FrameworkDeserialize(XmlReader, String)Deserializes the XML document contained by the specified XmlReader and encoding style.
Public methodDeserialize(XmlReader, XmlDeserializationEvents)Deserializes an XML document contained by the specified XmlReader and allows the overriding of events that occur during deserialization.
Public methodDeserialize(XmlReader, String, XmlDeserializationEvents)Infrastructure. Deserializes the object using the data contained by the specified XmlReader.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsEquals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Protected methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodStatic memberSupported by Portable Class LibraryFromMappings(XmlMapping[])Infrastructure. Returns an array of XmlSerializer objects created from an array of XmlTypeMapping objects.
Public methodStatic memberFromMappings(XmlMapping[], Evidence) Obsolete. Returns an instance of the XmlSerializer class created from mappings of one XML type to another.
Public methodStatic memberSupported by Portable Class LibraryFromMappings(XmlMapping[], Type)Infrastructure. Returns an instance of the XmlSerializer class from the specified mappings.
Public methodStatic memberSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsFromTypesReturns an array of XmlSerializer objects created from an array of types.
Public methodStatic memberGenerateSerializer(Type[], XmlMapping[])Infrastructure. Returns an assembly that contains custom-made serializers used to serialize or deserialize the specified type or types, using the specified mappings.
Public methodStatic memberGenerateSerializer(Type[], XmlMapping[], CompilerParameters)Infrastructure. Returns an assembly that contains custom-made serializers used to serialize or deserialize the specified type or types, using the specified mappings and compiler settings and options.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsGetHashCodeServes as the default hash function. (Inherited from Object.)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodStatic memberGetXmlSerializerAssemblyName(Type)Returns the name of the assembly that contains one or more versions of the XmlSerializer especially created to serialize or deserialize the specified type.
Public methodStatic memberGetXmlSerializerAssemblyName(Type, String)Returns the name of the assembly that contains the serializer for the specified type in the specified namespace.
Protected methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Protected methodSerialize(Object, XmlSerializationWriter)Infrastructure. Serializes the specified Object and writes the XML document to a file using the specified XmlSerializationWriter.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsSerialize(Stream, Object)Serializes the specified Object and writes the XML document to a file using the specified Stream.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsSerialize(TextWriter, Object)Serializes the specified Object and writes the XML document to a file using the specified TextWriter.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsSerialize(XmlWriter, Object)Serializes the specified Object and writes the XML document to a file using the specified XmlWriter.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsSerialize(Stream, Object, XmlSerializerNamespaces)Serializes the specified Object and writes the XML document to a file using the specified Streamthat references the specified namespaces.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsSerialize(TextWriter, Object, XmlSerializerNamespaces)Serializes the specified Object and writes the XML document to a file using the specified TextWriter and references the specified namespaces.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsSerialize(XmlWriter, Object, XmlSerializerNamespaces)Serializes the specified Object and writes the XML document to a file using the specified XmlWriter and references the specified namespaces.
Public methodSupported by the XNA FrameworkSerialize(XmlWriter, Object, XmlSerializerNamespaces, String)Serializes the specified object and writes the XML document to a file using the specified XmlWriter and references the specified namespaces and encoding style.
Public methodSerialize(XmlWriter, Object, XmlSerializerNamespaces, String, String)Serializes the specified Object and writes the XML document to a file using the specified XmlWriter, XML namespaces, and encoding.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsToStringReturns a string that represents the current object. (Inherited from Object.)
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  NameDescription
Public eventSupported by the XNA FrameworkUnknownAttributeOccurs when the XmlSerializer encounters an XML attribute of unknown type during deserialization.
Public eventSupported by the XNA FrameworkUnknownElementOccurs when the XmlSerializer encounters an XML element of unknown type during deserialization.
Public eventSupported by the XNA FrameworkUnknownNodeOccurs when the XmlSerializer encounters an XML node of unknown type during deserialization.
Public eventSupported by the XNA FrameworkUnreferencedObjectOccurs during deserialization of a SOAP-encoded XML stream, when the XmlSerializer encounters a recognized type that is not used or is unreferenced.
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XML serialization is the process of converting an object's public properties and fields to a serial format (in this case, XML) for storage or transport. Deserialization re-creates the object in its original state from the XML output. You can think of serialization as a way of saving the state of an object into a stream or buffer. For example, ASP.NET uses the XmlSerializer class to encode XML Web service messages.

The data in your objects is described using programming language constructs like classes, fields, properties, primitive types, arrays, and even embedded XML in the form of XmlElement or XmlAttribute objects. You have the option of creating your own classes, annotated with attributes, or using the XML Schema Definition Tool (Xsd.exe) to generate the classes based on an existing XML Schema definition (XSD) document. If you have an XML Schema, you can run the Xsd.exe to produce a set of classes that are strongly typed to the schema and annotated with attributes to adhere to the schema when serialized.

To transfer data between objects and XML requires a mapping from the programming language constructs to XML schema and from the XML schema to the programming language constructs. The XmlSerializer and related tools like Xsd.exe provide the bridge between these two technologies at both design time and runtime. At design time, use the Xsd.exe to produce an XML schema document (.xsd) from your custom classes or to produce classes from a given schema. In either case, the classes are annotated with custom attributes to instruct the XmlSerializer how to map between the XML schema system and the common language runtime. At runtime, instances of the classes can be serialized into XML documents that follow the given schema. Likewise, these XML documents can be deserialized into runtime objects. Note that the XML schema is optional, and not required at design time or runtime.

Controlling Generated XML

To control the generated XML, you can apply special attributes to classes and members. For example, to specify a different XML element name, apply an XmlElementAttribute to a public field or property, and set the ElementName property. For a complete list of similar attributes, see Attributes That Control XML Serialization. You can also implement the IXmlSerializable interface to control the XML output.

If the XML generated must conform to section 5 of the World Wide Consortium (www.w3.org) document, "Simple Object Access Protocol (SOAP) 1.1", you must construct the XmlSerializer with an XmlTypeMapping. To further control the encoded SOAP XML, use the attributes listed in Attributes That Control Encoded SOAP Serialization.

With the XmlSerializer you can take advantage of working with strongly typed classes and still have the flexibility of XML. Using fields or properties of type XmlElement, XmlAttribute or XmlNode in your strongly typed classes, you can read parts of the XML document directly into XML objects.

If you work with extensible XML schemas, you can also use the XmlAnyElementAttribute and XmlAnyAttributeAttribute attributes to serialize and deserialize elements or attributes that are not found in the original schema. To use the objects, apply an XmlAnyElementAttribute to a field that returns an array of XmlElement objects, or apply an XmlAnyAttributeAttribute to a field that returns an array of XmlAttribute objects.

If a property or field returns a complex object (such as an array or a class instance), the XmlSerializer converts it to an element nested within the main XML document. For example, the first class in the following code returns an instance of the second class.

No code example is currently available or this language may not be supported.

The serialized, XML output looks like this:

<MyClass>
  <MyObjectProperty>
  <ObjectName>My String</ObjectName>
  </MyObjectProperty>
</MyClass>

If a schema includes an element that is optional (minOccurs = '0'), or if the schema includes a default value, you have two options. One option is to use System.ComponentModel.DefaultValueAttribute to specify the default value, as shown in the following code.

No code example is currently available or this language may not be supported.

Another option is to use a special pattern to create a Boolean field recognized by the XmlSerializer, and to apply the XmlIgnoreAttribute to the field. The pattern is created in the form of propertyNameSpecified. For example, if there is a field named "MyFirstName" you would also create a field named "MyFirstNameSpecified" that instructs the XmlSerializer whether to generate the XML element named "MyFirstName". This is shown in the following example.

No code example is currently available or this language may not be supported.

Overriding Default Serialization

You can also override the serialization of any set of objects and their fields and properties by creating one of the appropriate attributes, and adding it to an instance of the XmlAttributes class. Overriding serialization in this way has two uses: first, you can control and augment the serialization of objects found in a DLL, even if you do not have access to the source; second, you can create one set of serializable classes, but serialize the objects in multiple ways. For more details, see the XmlAttributeOverrides class and How to: Control Serialization of Derived Classes.

To serialize an object, call the Serialize method. To deserialize an object, call the Deserialize method.

To add XML namespaces to an XML document, see XmlSerializerNamespaces.

NoteNote

The XmlSerializer gives special treatment to classes that implement IEnumerable or ICollection. A class that implements IEnumerable must implement a public Add method that takes a single parameter. The Add method's parameter must be of the same type as is returned from the Current property on the value returned from GetEnumerator, or one of that type's bases. A class that implements ICollection (such as CollectionBase) in addition to IEnumerable must have a public Item indexed property (indexer in C#) that takes an integer, and it must have a public Count property of type integer. The parameter to the Add method must be the same type as is returned from the Item property, or one of that type's bases. For classes that implement ICollection, values to be serialized are retrieved from the indexed Item property, not by calling GetEnumerator.

You must have permission to write to the temporary directory (as defined by the TEMP environment variable) to deserialize an object.

Dynamically Generated Assemblies

To increase performance, the XML serialization infrastructure dynamically generates assemblies to serialize and deserialize specified types. The infrastructure finds and reuses those assemblies. This behavior occurs only when using the following constructors:

XmlSerializer.XmlSerializer(Type)

XmlSerializer.XmlSerializer(Type, String)

If you use any of the other constructors, multiple versions of the same assembly are generated and never unloaded, which results in a memory leak and poor performance. The easiest solution is to use one of the previously mentioned two constructors. Otherwise, you must cache the assemblies in a Hashtable, as shown in the following example.

No code example is currently available or this language may not be supported.

Serialization of ArrayList and Generic List

The XmlSerializer cannot serialize or deserialize the following:

Serialization of Enumerations of Unsigned Long

The XmlSerializer cannot be instantiated to serialize an enumeration if the following conditions are true: The enumeration is of type unsigned long (ulong in C#) and the enumeration contains any member with a value larger than 9,223,372,036,854,775,807. For example, the following cannot be serialized.

public enum LargeNumbers: ulong
{
    a = 9223372036854775808
}
// At runtime, the following code will fail.
xmlSerializer mySerializer=new XmlSerializer(typeof(LargeNumbers));

Objects marked with the Obsolete Attribute no longer serialized

In the .NET Framework 3.5 the XmlSerializer class no longer serializes objects that are marked as [Obsolete].

The following example contains two main classes: PurchaseOrder and Test. The PurchaseOrder class contains information about a single purchase. The Test class contains the methods that create the purchase order, and that read the created purchase order.

No code example is currently available or this language may not be supported.

.NET Framework

Supported in: 4.5.2, 4.5.1, 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 8, Silverlight 8.1

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.

This type is thread safe.

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