[アーティクル]
11/18/2011

XElement Class

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Represents an XML element.

Inheritance Hierarchy

System.Object
  System.Xml.Linq.XObject
    System.Xml.Linq.XNode
      System.Xml.Linq.XContainer
        System.Xml.Linq.XElement

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

Syntax

'Declaration
<XmlSchemaProviderAttribute(Nothing, IsAny := True)> _
Public Class XElement _
    Inherits XContainer _
    Implements IXmlSerializable

[XmlSchemaProviderAttribute(null, IsAny = true)]
public class XElement : XContainer, IXmlSerializable

The XElement type exposes the following members.

Constructors

	Name	Description
	XElement(XElement)	Initializes a new instance of the XElement class from another XElement object.
	XElement(XName)	Initializes a new instance of the XElement class with the specified name.
	XElement(XStreamingElement)	Initializes a new instance of the XElement class from an XStreamingElement object.
	XElement(XName, Object)	Initializes a new instance of the XElement class with the specified name and content.
	XElement(XName, array<Object[])	Initializes a new instance of the XElement class with the specified name and content.

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Properties

	Name	Description
	BaseUri	Gets the base URI for this XObject. (Inherited from XObject.)
	Document	Gets the XDocument for this XObject. (Inherited from XObject.)
	EmptySequence	Gets an empty collection of elements.
	FirstAttribute	Gets the first attribute of this element.
	FirstNode	Get the first child node of this node. (Inherited from XContainer.)
	HasAttributes	Gets a value indicating whether this element as at least one attribute.
	HasElements	Gets a value indicating whether this element has at least one child element.
	IsEmpty	Gets a value indicating whether this element contains no content.
	LastAttribute	Gets the last attribute of this element.
	LastNode	Get the last child node of this node. (Inherited from XContainer.)
	Name	Gets the name of this element.
	NextNode	Gets the next sibling node of this node. (Inherited from XNode.)
	NodeType	Gets the node type for this node. (Overrides XObject.NodeType.)
	Parent	Gets the parent XElement of this XObject. (Inherited from XObject.)
	PreviousNode	Gets the previous sibling node of this node. (Inherited from XNode.)
	Value	Gets the concatenated text contents of this element.

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Methods

	Name	Description
	Add(Object)	Adds the specified content as children of this XContainer. (Inherited from XContainer.)
	Add(array<Object[])	Adds the specified content as children of this XContainer. (Inherited from XContainer.)
	AddAfterSelf(Object)	Adds the specified content immediately after this node. (Inherited from XNode.)
	AddAfterSelf(array<Object[])	Adds the specified content immediately after this node. (Inherited from XNode.)
	AddAnnotation	Adds an object to the annotation list of this XObject. (Inherited from XObject.)
	AddBeforeSelf(Object)	Adds the specified content immediately before this node. (Inherited from XNode.)
	AddBeforeSelf(array<Object[])	Adds the specified content immediately before this node. (Inherited from XNode.)
	AddFirst(Object)	Adds the specified content as the first children of this document or element. (Inherited from XContainer.)
	AddFirst(array<Object[])	Adds the specified content as the first children of this document or element. (Inherited from XContainer.)
	Ancestors()	Returns a collection of the ancestor elements of this node. (Inherited from XNode.)
	Ancestors(XName)	Returns a filtered collection of the ancestor elements of this node. Only elements that have a matching XName are included in the collection. (Inherited from XNode.)
	AncestorsAndSelf()	Returns a collection of elements that contain this element, and the ancestors of this element.
	AncestorsAndSelf(XName)	Returns a filtered collection of elements that contain this element, and the ancestors of this element. Only elements that have a matching XName are included in the collection.
	Annotation(Type)	Gets the first annotation object of the specified type from this XObject. (Inherited from XObject.)
	Annotation<T>()	Get the first annotation object of the specified type from this XObject. (Inherited from XObject.)
	Annotations(Type)	Gets a collection of annotations of the specified type for this XObject. (Inherited from XObject.)
	Annotations<T>()	Gets a collection of annotations of the specified type for this XObject. (Inherited from XObject.)
	Attribute	Returns the XAttribute of this XElement that has the specified XName.
	Attributes()	Returns a collection of attributes of this element.
	Attributes(XName)	Returns a filtered collection of attributes of this element. Only elements that have a matching XName are included in the collection.
	CreateReader()	Creates an XmlReader for this node. (Inherited from XNode.)
	CreateReader(ReaderOptions)	Creates an XmlReader for this node. (Inherited from XNode.)
	CreateWriter	Creates an XmlWriter that can be used to add nodes to the XContainer. (Inherited from XContainer.)
	DescendantNodes	Returns a collection of the descendant nodes for this document or element, in document order. (Inherited from XContainer.)
	DescendantNodesAndSelf	Returns a collection of nodes that contain this element, and all descendant nodes of this element, in document order.
	Descendants()	Returns a collection of the descendant elements for this document or element, in document order. (Inherited from XContainer.)
	Descendants(XName)	Returns a filtered collection of the descendant elements for this document or element, in document order. Only elements that have a matching XName are included in the collection. (Inherited from XContainer.)
	DescendantsAndSelf()	Returns a collection of elements that contain this element, and all descendant elements of this element, in document order.
	DescendantsAndSelf(XName)	Returns a filtered collection of elements that contain this element, and all descendant elements of this element, in document order. Only elements that have a matching XName are included in the collection.
	Element	Gets the first (in document order) child element with the specified XName. (Inherited from XContainer.)
	Elements()	Returns a collection of the child elements of this element or document, in document order. (Inherited from XContainer.)
	Elements(XName)	Returns a filtered collection of the child elements of this element or document, in document order. Only elements that have a matching XName are included in the collection. (Inherited from XContainer.)
	ElementsAfterSelf()	Returns a collection of the sibling elements after this node, in document order. (Inherited from XNode.)
	ElementsAfterSelf(XName)	Returns a filtered collection of the sibling elements after this node, in document order. Only elements that have a matching XName are included in the collection. (Inherited from XNode.)
	ElementsBeforeSelf()	Returns a collection of the sibling elements before this node, in document order. (Inherited from XNode.)
	ElementsBeforeSelf(XName)	Returns a filtered collection of the sibling elements before this node, in document order. Only elements that have a matching XName are included in the collection. (Inherited from XNode.)
	Equals(Object)	Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
	Finalize	Allows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)
	GetDefaultNamespace	Gets the default XNamespace of this XElement.
	GetHashCode	Serves as a hash function for a particular type. (Inherited from Object.)
	GetNamespaceOfPrefix	Gets the namespace associated with a particular prefix for this XElement.
	GetPrefixOfNamespace	Gets the prefix associated with a namespace for this XElement.
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	IsAfter	Determines if the current node appears after a specified node in terms of document order. (Inherited from XNode.)
	IsBefore	Determines if the current node appears before a specified node in terms of document order. (Inherited from XNode.)
	Load(Stream)	Creates a new XElement instance using the specified stream.
	Load(String)	Loads an XElement from a file located in the applications' XAP package.
	Load(TextReader)	Loads an XElement from a TextReader.
	Load(XmlReader)	Loads an XElement from an XmlReader.
	Load(Stream, LoadOptions)	Creates a new XElement instance using the specified stream, optionally preserving white space, setting the base URI, and retaining line information.
	Load(String, LoadOptions)	Loads an XElement from a file located in the application's XAP package, optionally preserving white space, setting the base URI, and retaining line information.
	Load(TextReader, LoadOptions)	Loads an XElement from a TextReader, optionally preserving white space and retaining line information.
	Load(XmlReader, LoadOptions)	Loads an XElement from an XmlReader, optionally preserving white space, setting the base URI, and retaining line information.
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	Nodes	Returns a collection of the child nodes of this element or document, in document order. (Inherited from XContainer.)
	NodesAfterSelf	Returns a collection of the sibling nodes after this node, in document order. (Inherited from XNode.)
	NodesBeforeSelf	Returns a collection of the sibling nodes before this node, in document order. (Inherited from XNode.)
	Parse(String)	Load an XElement from a string that contains XML.
	Parse(String, LoadOptions)	Load an XElement from a string that contains XML, optionally preserving white space and retaining line information.
	Remove	Removes this node from its parent. (Inherited from XNode.)
	RemoveAll	Removes nodes and attributes from this XElement.
	RemoveAnnotations(Type)	Removes the annotations of the specified type from this XObject. (Inherited from XObject.)
	RemoveAnnotations<T>()	Removes the annotations of the specified type from this XObject. (Inherited from XObject.)
	RemoveAttributes	Removes the attributes of this XElement.
	RemoveNodes	Removes the child nodes from this document or element. (Inherited from XContainer.)
	ReplaceAll(Object)	Replaces the child nodes and the attributes of this element with the specified content.
	ReplaceAll(array<Object[])	Replaces the child nodes and the attributes of this element with the specified content.
	ReplaceAttributes(Object)	Replaces the attributes of this element with the specified content.
	ReplaceAttributes(array<Object[])	Replaces the attributes of this element with the specified content.
	ReplaceNodes(Object)	Replaces the children nodes of this document or element with the specified content. (Inherited from XContainer.)
	ReplaceNodes(array<Object[])	Replaces the children nodes of this document or element with the specified content. (Inherited from XContainer.)
	ReplaceWith(Object)	Replaces this node with the specified content. (Inherited from XNode.)
	ReplaceWith(array<Object[])	Replaces this node with the specified content. (Inherited from XNode.)
	Save(Stream)	Outputs this XElement to the specified Stream.
	Save(TextWriter)	Serialize this element to a TextWriter.
	Save(XmlWriter)	Serialize this element to an XmlWriter.
	Save(Stream, SaveOptions)	Outputs this XElement to the specified Stream, optionally specifying formatting behavior.
	Save(TextWriter, SaveOptions)	Serialize this element to a TextWriter, optionally disabling formatting.
	SetAttributeValue	Sets the value of an attribute, adds an attribute, or removes an attribute.
	SetElementValue	Sets the value of a child element, adds a child element, or removes a child element.
	SetValue	Sets the value of this element.
	ToString()	Returns the indented XML for this node. (Inherited from XNode.)
	ToString(SaveOptions)	Returns the XML for this node, optionally disabling formatting. (Inherited from XNode.)
	WriteTo	Write this element to an XmlWriter. (Overrides XNode.WriteTo(XmlWriter).)

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Events

	Name	Description
	Changed	Raised when this XObject or any of its descendants have changed. (Inherited from XObject.)
	Changing	Raised when this XObject or any of its descendants are about to change. (Inherited from XObject.)

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Operators

	Name	Description
	Explicit(XElement to DateTime)	Cast the value of this XElement to a DateTime.
	Explicit(XElement to Decimal)	Cast the value of this XElement to a Decimal.
	Explicit(XElement to Nullable<Decimal>)	Cast the value of this XElement to a Nullable<T> of Decimal.
	Explicit(XElement to Nullable<Single>)	Cast the value of this XElement to a Nullable<T> of Single.
	Explicit(XElement to TimeSpan)	Cast the value of this XElement to a TimeSpan.
	Explicit(XElement to Nullable<Double>)	Cast the value of this XElement to a Nullable<T> of Double.
	Explicit(XElement to Double)	Cast the value of this XElement to a Double.
	Explicit(XElement to Single)	Cast the value of this XElement to a Single.
	Explicit(XElement to Guid)	Cast the value of this XElement to a Guid.
	Explicit(XElement to Nullable<Guid>)	Cast the value of this XElement to a Nullable<T> of Guid.
	Explicit(XElement to Nullable<TimeSpan>)	Cast the value of this XElement to a Nullable<T> of TimeSpan.
	Explicit(XElement to Nullable<DateTime>)	Cast the value of this XElement to a Nullable<T> of DateTime.
	Explicit(XElement to DateTimeOffset)	Cast the value of this XAttribute to a DateTimeOffset.
	Explicit(XElement to Nullable<DateTimeOffset>)	Cast the value of this XElement to a Nullable<T> of DateTimeOffset.
	Explicit(XElement to Int32)	Cast the value of this XElement to an Int32.
	Explicit(XElement to Nullable<Int32>)	Cast the value of this XElement to a Nullable<T> of Int32.
	Explicit(XElement to Nullable<Boolean>)	Cast the value of this XElement to a Nullable<T> of Boolean.
	Explicit(XElement to String)	Cast the value of this XElement to a String.
	Explicit(XElement to Boolean)	Cast the value of this XElement to a Boolean.
	Explicit(XElement to UInt32)	Cast the value of this XElement to a UInt32.
	Explicit(XElement to UInt64)	Cast the value of this XElement to a UInt64.
	Explicit(XElement to Nullable<UInt64>)	Cast the value of this XElement to a Nullable<T> of UInt64.
	Explicit(XElement to Nullable<Int64>)	Cast the value of this XElement to a Nullable<T> of Int64.
	Explicit(XElement to Nullable<UInt32>)	Cast the value of this XElement to a Nullable<T> of UInt32.
	Explicit(XElement to Int64)	Cast the value of this XElement to an Int64.

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Extension Methods

	Name	Description
	CreateNavigator()	Overloaded. Creates an XPathNavigator for an XNode. (Defined by Extensions.)
	CreateNavigator(XmlNameTable)	Overloaded. Creates an XPathNavigator for an XNode. The XmlNameTable enables more efficient XPath expression processing. (Defined by Extensions.)
	XPathEvaluate(String)	Overloaded. Evaluates an XPath expression. (Defined by Extensions.)
	XPathEvaluate(String, IXmlNamespaceResolver)	Overloaded. Evaluates an XPath expression, resolving namespace prefixes using the specified IXmlNamespaceResolver. (Defined by Extensions.)
	XPathSelectElement(String)	Overloaded. Selects an XElement using a XPath expression. (Defined by Extensions.)
	XPathSelectElement(String, IXmlNamespaceResolver)	Overloaded. Selects an XElement using a XPath expression, resolving namespace prefixes using the specified IXmlNamespaceResolver. (Defined by Extensions.)
	XPathSelectElements(String)	Overloaded. Selects a collection of elements using an XPath expression. (Defined by Extensions.)
	XPathSelectElements(String, IXmlNamespaceResolver)	Overloaded. Selects a collection of elements using an XPath expression, resolving namespace prefixes using the specified IXmlNamespaceResolver. (Defined by Extensions.)

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Explicit Interface Implementations

	Name	Description
	IXmlLineInfo.HasLineInfo	Gets a value indicating whether or not this XObject has line information. (Inherited from XObject.)
	IXmlLineInfo.LineNumber	Gets the line number that the underlying XmlReader reported for this XObject. (Inherited from XObject.)
	IXmlLineInfo.LinePosition	Gets the line position that the underlying XmlReader reported for this XObject. (Inherited from XObject.)
	IXmlSerializable.GetSchema	Gets an XML schema definition that describes the XML representation of this object.
	IXmlSerializable.ReadXml	Generates an object from its XML representation.
	IXmlSerializable.WriteXml	Converts an object into its XML representation.

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Remarks

This class represents an XML element, the fundamental XML construct.

An element has an XName, optionally one or more attributes, and can optionally contain content. For more information, see Nodes.

An XElement can contain the following types of content:

For more information about the valid content of an XElement, see Valid Content of XElement and XDocument Objects in the .NET Framework documentation.

XElement derives from XContainer, which derives from XNode.

Some XElement methods can be used from XAML. For more information, see LINQ to XML Dynamic Properties in the .NET Framework documentation.

Examples

The following example creates an XML tree. The content of the new element comes from a LINQ query.

Dim output As New StringBuilder
Dim xmlTree1 As XElement = _
        <Root>
            <Child1>1</Child1>
            <Child2>2</Child2>
            <Child3>3</Child3>
            <Child4>4</Child4>
            <Child5>5</Child5>
            <Child6>6</Child6>
        </Root>

Dim xmlTree2 As XElement = _
    <Root>
        <%= From el In xmlTree1.Elements() _
            Where el.Value >= 3 And el.Value <= 5 _
            Select el %>
    </Root>

output.Append(xmlTree2)
output.Append(Environment.NewLine)


OutputTextBlock.Text = output.ToString()

StringBuilder output = new StringBuilder();
XElement xmlTree1 = new XElement("Root",
    new XElement("Child1", 1),
    new XElement("Child2", 2),
    new XElement("Child3", 3),
    new XElement("Child4", 4),
    new XElement("Child5", 5),
    new XElement("Child6", 6)
);

XElement xmlTree2 = new XElement("Root",
    from el in xmlTree1.Elements()
    where ((int)el >= 3 && (int)el <= 5)
    select el
);
output.Append(xmlTree2 + Environment.NewLine);

OutputTextBlock.Text = output.ToString();

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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