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XmlTextReader Class

.NET Framework 4

Other Versions

Represents a reader that provides fast, non-cached, forward-only access to XML data.

Inheritance Hierarchy

System.Object
System.Xml.XmlReader
System.Xml.XmlTextReader

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

Syntax

C++

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[PermissionSetAttribute(SecurityAction.InheritanceDemand, Name = "FullTrust")]
public class XmlTextReader : XmlReader, 
	IXmlLineInfo, IXmlNamespaceResolver

The XmlTextReader type exposes the following members.

Constructors

	Name	Description
	XmlTextReader()	Initializes a new instance of the XmlTextReader.
	XmlTextReader(Stream)	Initializes a new instance of the XmlTextReader class with the specified stream.
	XmlTextReader(String)	Initializes a new instance of the XmlTextReader class with the specified file.
	XmlTextReader(TextReader)	Initializes a new instance of the XmlTextReader class with the specified TextReader.
	XmlTextReader(XmlNameTable)	Infrastructure. Initializes a new instance of the XmlTextReader class with the specified XmlNameTable.
	XmlTextReader(Stream, XmlNameTable)	Initializes a new instance of the XmlTextReader class with the specified stream and XmlNameTable.
	XmlTextReader(String, Stream)	Initializes a new instance of the XmlTextReader class with the specified URL and stream.
	XmlTextReader(String, TextReader)	Initializes a new instance of the XmlTextReader class with the specified URL and TextReader.
	XmlTextReader(String, XmlNameTable)	Initializes a new instance of the XmlTextReader class with the specified file and XmlNameTable.
	XmlTextReader(TextReader, XmlNameTable)	Initializes a new instance of the XmlTextReader class with the specified TextReader and XmlNameTable.
	XmlTextReader(Stream, XmlNodeType, XmlParserContext)	Initializes a new instance of the XmlTextReader class with the specified stream, XmlNodeType, and XmlParserContext.
	XmlTextReader(String, Stream, XmlNameTable)	Initializes a new instance of the XmlTextReader class with the specified URL, stream and XmlNameTable.
	XmlTextReader(String, TextReader, XmlNameTable)	Initializes a new instance of the XmlTextReader class with the specified URL, TextReader and XmlNameTable.
	XmlTextReader(String, XmlNodeType, XmlParserContext)	Initializes a new instance of the XmlTextReader class with the specified string, XmlNodeType, and XmlParserContext.

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Properties

	Name	Description
	AttributeCount	Gets the number of attributes on the current node. (Overrides XmlReader.AttributeCount.)
	BaseURI	Gets the base URI of the current node. (Overrides XmlReader.BaseURI.)
	CanReadBinaryContent	Gets a value indicating whether the XmlTextReader implements the binary content read methods. (Overrides XmlReader.CanReadBinaryContent.)
	CanReadValueChunk	Gets a value indicating whether the XmlTextReader implements the ReadValueChunk method. (Overrides XmlReader.CanReadValueChunk.)
	CanResolveEntity	Gets a value indicating whether this reader can parse and resolve entities. (Overrides XmlReader.CanResolveEntity.)
	Depth	Gets the depth of the current node in the XML document. (Overrides XmlReader.Depth.)
	DtdProcessing	Gets or sets the DtdProcessing enumeration.
	Encoding	Gets the encoding of the document.
	EntityHandling	Gets or sets a value that specifies how the reader handles entities.
	EOF	Gets a value indicating whether the reader is positioned at the end of the stream. (Overrides XmlReader.EOF.)
	HasAttributes	Gets a value indicating whether the current node has any attributes. (Inherited from XmlReader.)
	HasValue	Gets a value indicating whether the current node can have a Value other than String.Empty. (Overrides XmlReader.HasValue.)
	IsDefault	Gets a value indicating whether the current node is an attribute that was generated from the default value defined in the DTD or schema. (Overrides XmlReader.IsDefault.)
	IsEmptyElement	Gets a value indicating whether the current node is an empty element (for example, <MyElement/>). (Overrides XmlReader.IsEmptyElement.)
	Item[Int32]	When overridden in a derived class, gets the value of the attribute with the specified index. (Inherited from XmlReader.)
	Item[String]	When overridden in a derived class, gets the value of the attribute with the specified Name. (Inherited from XmlReader.)
	Item[String, String]	When overridden in a derived class, gets the value of the attribute with the specified LocalName and NamespaceURI. (Inherited from XmlReader.)
	LineNumber	Gets the current line number.
	LinePosition	Gets the current line position.
	LocalName	Gets the local name of the current node. (Overrides XmlReader.LocalName.)
	Name	Gets the qualified name of the current node. (Overrides XmlReader.Name.)
	Namespaces	Gets or sets a value indicating whether to do namespace support.
	NamespaceURI	Gets the namespace URI (as defined in the W3C Namespace specification) of the node on which the reader is positioned. (Overrides XmlReader.NamespaceURI.)
	NameTable	Gets the XmlNameTable associated with this implementation. (Overrides XmlReader.NameTable.)
	NodeType	Gets the type of the current node. (Overrides XmlReader.NodeType.)
	Normalization	Gets or sets a value indicating whether to normalize white space and attribute values.
	Prefix	Gets the namespace prefix associated with the current node. (Overrides XmlReader.Prefix.)
	ProhibitDtd	Obsolete. Gets or sets a value indicating whether to allow DTD processing. This property is obsolete. Use DtdProcessing instead.
	QuoteChar	Gets the quotation mark character used to enclose the value of an attribute node. (Overrides XmlReader.QuoteChar.)
	ReadState	Gets the state of the reader. (Overrides XmlReader.ReadState.)
	SchemaInfo	Gets the schema information that has been assigned to the current node as a result of schema validation. (Inherited from XmlReader.)
	Settings	Gets the XmlReaderSettings object used to create this XmlReader instance. (Inherited from XmlReader.) In XNA Framework, this member is overridden by Settings.
	Value	Gets the text value of the current node. (Overrides XmlReader.Value.)
	ValueType	Gets The Common Language Runtime (CLR) type for the current node. (Inherited from XmlReader.)
	WhitespaceHandling	Gets or sets a value that specifies how white space is handled.
	XmlLang	Gets the current xml:lang scope. (Overrides XmlReader.XmlLang.)
	XmlResolver	Sets the XmlResolver used for resolving DTD references.
	XmlSpace	Gets the current xml:space scope. (Overrides XmlReader.XmlSpace.)

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Methods

	Name	Description
	Close	Changes the ReadState to Closed. (Overrides XmlReader.Close().)
	Dispose(Boolean)	Releases the unmanaged resources used by the XmlReader and optionally releases the managed resources. (Inherited from XmlReader.)
	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 it is reclaimed by garbage collection. (Inherited from Object.)
	GetAttribute(Int32)	Gets the value of the attribute with the specified index. (Overrides XmlReader.GetAttribute(Int32).)
	GetAttribute(String)	Gets the value of the attribute with the specified name. (Overrides XmlReader.GetAttribute(String).)
	GetAttribute(String, String)	Gets the value of the attribute with the specified local name and namespace URI. (Overrides XmlReader.GetAttribute(String, String).)
	GetHashCode	Serves as a hash function for a particular type. (Inherited from Object.)
	GetNamespacesInScope	Gets a collection that contains all namespaces currently in-scope.
	GetRemainder	Gets the remainder of the buffered XML.
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	HasLineInfo	Gets a value indicating whether the class can return line information.
	IsStartElement()	Calls MoveToContent and tests if the current content node is a start tag or empty element tag. (Inherited from XmlReader.)
	IsStartElement(String)	Calls MoveToContent and tests if the current content node is a start tag or empty element tag and if the Name property of the element found matches the given argument. (Inherited from XmlReader.)
	IsStartElement(String, String)	Calls MoveToContent and tests if the current content node is a start tag or empty element tag and if the LocalName and NamespaceURI properties of the element found match the given strings. (Inherited from XmlReader.)
	LookupNamespace	Resolves a namespace prefix in the current element's scope. (Overrides XmlReader.LookupNamespace(String).)
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	MoveToAttribute(Int32)	Moves to the attribute with the specified index. (Overrides XmlReader.MoveToAttribute(Int32).)
	MoveToAttribute(String)	Moves to the attribute with the specified name. (Overrides XmlReader.MoveToAttribute(String).)
	MoveToAttribute(String, String)	Moves to the attribute with the specified local name and namespace URI. (Overrides XmlReader.MoveToAttribute(String, String).)
	MoveToContent	Checks whether the current node is a content (non-white space text, CDATA, Element, EndElement, EntityReference, or EndEntity) node. If the node is not a content node, the reader skips ahead to the next content node or end of file. It skips over nodes of the following type: ProcessingInstruction, DocumentType, Comment, Whitespace, or SignificantWhitespace. (Inherited from XmlReader.)
	MoveToElement	Moves to the element that contains the current attribute node. (Overrides XmlReader.MoveToElement().)
	MoveToFirstAttribute	Moves to the first attribute. (Overrides XmlReader.MoveToFirstAttribute().)
	MoveToNextAttribute	Moves to the next attribute. (Overrides XmlReader.MoveToNextAttribute().)
	Read	Reads the next node from the stream. (Overrides XmlReader.Read().)
	ReadAttributeValue	Parses the attribute value into one or more Text, EntityReference, or EndEntity nodes. (Overrides XmlReader.ReadAttributeValue().)
	ReadBase64	Decodes Base64 and returns the decoded binary bytes.
	ReadBinHex	Decodes BinHex and returns the decoded binary bytes.
	ReadChars	Reads the text contents of an element into a character buffer. This method is designed to read large streams of embedded text by calling it successively.
	ReadContentAs	Reads the content as an object of the type specified. (Inherited from XmlReader.)
	ReadContentAsBase64	Reads the content and returns the Base64 decoded binary bytes. (Overrides XmlReader.ReadContentAsBase64(Byte[], Int32, Int32).)
	ReadContentAsBinHex	Reads the content and returns the BinHex decoded binary bytes. (Overrides XmlReader.ReadContentAsBinHex(Byte[], Int32, Int32).)
	ReadContentAsBoolean	Reads the text content at the current position as a Boolean. (Inherited from XmlReader.)
	ReadContentAsDateTime	Reads the text content at the current position as a DateTime object. (Inherited from XmlReader.)
	ReadContentAsDecimal	Reads the text content at the current position as a Decimal object. (Inherited from XmlReader.)
	ReadContentAsDouble	Reads the text content at the current position as a double-precision floating-point number. (Inherited from XmlReader.)
	ReadContentAsFloat	Reads the text content at the current position as a single-precision floating point number. (Inherited from XmlReader.)
	ReadContentAsInt	Reads the text content at the current position as a 32-bit signed integer. (Inherited from XmlReader.)
	ReadContentAsLong	Reads the text content at the current position as a 64-bit signed integer. (Inherited from XmlReader.)
	ReadContentAsObject	Reads the text content at the current position as an Object. (Inherited from XmlReader.)
	ReadContentAsString	Reads the text content at the current position as a String object. (Inherited from XmlReader.)
	ReadElementContentAs(Type, IXmlNamespaceResolver)	Reads the element content as the requested type. (Inherited from XmlReader.)
	ReadElementContentAs(Type, IXmlNamespaceResolver, String, String)	Checks that the specified local name and namespace URI matches that of the current element, then reads the element content as the requested type. (Inherited from XmlReader.)
	ReadElementContentAsBase64	Reads the element and decodes the Base64 content. (Overrides XmlReader.ReadElementContentAsBase64(Byte[], Int32, Int32).)
	ReadElementContentAsBinHex	Reads the element and decodes the BinHex content. (Overrides XmlReader.ReadElementContentAsBinHex(Byte[], Int32, Int32).)
	ReadElementContentAsBoolean()	Reads the current element and returns the contents as a Boolean object. (Inherited from XmlReader.)
	ReadElementContentAsBoolean(String, String)	Checks that the specified local name and namespace URI matches that of the current element, then reads the current element and returns the contents as a Boolean object. (Inherited from XmlReader.)
	ReadElementContentAsDateTime()	Reads the current element and returns the contents as a DateTime object. (Inherited from XmlReader.)
	ReadElementContentAsDateTime(String, String)	Checks that the specified local name and namespace URI matches that of the current element, then reads the current element and returns the contents as a DateTime object. (Inherited from XmlReader.)
	ReadElementContentAsDecimal()	Reads the current element and returns the contents as a Decimal object. (Inherited from XmlReader.)
	ReadElementContentAsDecimal(String, String)	Checks that the specified local name and namespace URI matches that of the current element, then reads the current element and returns the contents as a Decimal object. (Inherited from XmlReader.)
	ReadElementContentAsDouble()	Reads the current element and returns the contents as a double-precision floating-point number. (Inherited from XmlReader.)
	ReadElementContentAsDouble(String, String)	Checks that the specified local name and namespace URI matches that of the current element, then reads the current element and returns the contents as a double-precision floating-point number. (Inherited from XmlReader.)
	ReadElementContentAsFloat()	Reads the current element and returns the contents as single-precision floating-point number. (Inherited from XmlReader.)
	ReadElementContentAsFloat(String, String)	Checks that the specified local name and namespace URI matches that of the current element, then reads the current element and returns the contents as a single-precision floating-point number. (Inherited from XmlReader.)
	ReadElementContentAsInt()	Reads the current element and returns the contents as a 32-bit signed integer. (Inherited from XmlReader.)
	ReadElementContentAsInt(String, String)	Checks that the specified local name and namespace URI matches that of the current element, then reads the current element and returns the contents as a 32-bit signed integer. (Inherited from XmlReader.)
	ReadElementContentAsLong()	Reads the current element and returns the contents as a 64-bit signed integer. (Inherited from XmlReader.)
	ReadElementContentAsLong(String, String)	Checks that the specified local name and namespace URI matches that of the current element, then reads the current element and returns the contents as a 64-bit signed integer. (Inherited from XmlReader.)
	ReadElementContentAsObject()	Reads the current element and returns the contents as an Object. (Inherited from XmlReader.)
	ReadElementContentAsObject(String, String)	Checks that the specified local name and namespace URI matches that of the current element, then reads the current element and returns the contents as an Object. (Inherited from XmlReader.)
	ReadElementContentAsString()	Reads the current element and returns the contents as a String object. (Inherited from XmlReader.)
	ReadElementContentAsString(String, String)	Checks that the specified local name and namespace URI matches that of the current element, then reads the current element and returns the contents as a String object. (Inherited from XmlReader.)
	ReadElementString()	Reads a text-only element. (Inherited from XmlReader.)
	ReadElementString(String)	Checks that the Name property of the element found matches the given string before reading a text-only element. (Inherited from XmlReader.)
	ReadElementString(String, String)	Checks that the LocalName and NamespaceURI properties of the element found matches the given strings before reading a text-only element. (Inherited from XmlReader.)
	ReadEndElement	Checks that the current content node is an end tag and advances the reader to the next node. (Inherited from XmlReader.)
	ReadInnerXml	When overridden in a derived class, reads all the content, including markup, as a string. (Inherited from XmlReader.)
	ReadOuterXml	When overridden in a derived class, reads the content, including markup, representing this node and all its children. (Inherited from XmlReader.)
	ReadStartElement()	Checks that the current node is an element and advances the reader to the next node. (Inherited from XmlReader.)
	ReadStartElement(String)	Checks that the current content node is an element with the given Name and advances the reader to the next node. (Inherited from XmlReader.)
	ReadStartElement(String, String)	Checks that the current content node is an element with the given LocalName and NamespaceURI and advances the reader to the next node. (Inherited from XmlReader.)
	ReadString	Reads the contents of an element or a text node as a string. (Overrides XmlReader.ReadString().)
	ReadSubtree	Returns a new XmlReader instance that can be used to read the current node, and all its descendants. (Inherited from XmlReader.)
	ReadToDescendant(String)	Advances the XmlReader to the next descendant element with the specified qualified name. (Inherited from XmlReader.)
	ReadToDescendant(String, String)	Advances the XmlReader to the next descendant element with the specified local name and namespace URI. (Inherited from XmlReader.)
	ReadToFollowing(String)	Reads until an element with the specified qualified name is found. (Inherited from XmlReader.)
	ReadToFollowing(String, String)	Reads until an element with the specified local name and namespace URI is found. (Inherited from XmlReader.)
	ReadToNextSibling(String)	Advances the XmlReader to the next sibling element with the specified qualified name. (Inherited from XmlReader.)
	ReadToNextSibling(String, String)	Advances the XmlReader to the next sibling element with the specified local name and namespace URI. (Inherited from XmlReader.)
	ReadValueChunk	Reads large streams of text embedded in an XML document. (Inherited from XmlReader.)
	ResetState	Resets the state of the reader to ReadState.Initial.
	ResolveEntity	Resolves the entity reference for EntityReference nodes. (Overrides XmlReader.ResolveEntity().)
	Skip	Skips the children of the current node. (Overrides XmlReader.Skip().)
	ToString	Returns a string that represents the current object. (Inherited from Object.)

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Explicit Interface Implementations

	Name	Description
	IDisposable.Dispose	For a description of this member, see IDisposable.Dispose. (Inherited from XmlReader.)
	IXmlNamespaceResolver.GetNamespacesInScope	For a description of this member, see IXmlNamespaceResolver.GetNamespacesInScope.
	IXmlNamespaceResolver.LookupNamespace	For a description of this member, see IXmlNamespaceResolver.LookupNamespace.
	IXmlNamespaceResolver.LookupPrefix	For a description of this member, see IXmlNamespaceResolver.LookupPrefix.

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Remarks

Note
In the .NET Framework version 2.0 release, the recommended practice is to create XmlReader instances using the XmlReader.Create method. This allows you to take full advantage of the new features introduced in this release. For more information, see Creating XML Readers.

XmlTextReader provides forward-only, read-only access to a stream of XML data. The current node refers to the node on which the reader is positioned. The reader is advanced using any of the read methods and properties reflect the value of the current node.

This class implements XmlReader and conforms to the W3C Extensible Markup Language (XML) 1.0 and the Namespaces in XML recommendations. XmlTextReader provides the following functionality:

Enforces the rules of well-formed XML.
XmlTextReader does not provide data validation.
Checks that DocumentType nodes are well-formed. XmlTextReader checks the DTD for well-formedness, but does not validate using the DTD.
For nodes where NodeType is XmlNodeType.EntityReference, a single empty EntityReference node is returned (that is, the Value property is String.Empty).

Note
The actual declarations of entities in the DTD are called Entity nodes. When you refer to these nodes in your data, they are called EntityReference nodes.

Does not expand default attributes.

Because the XmlTextReader does not perform the extra checks required for data validation, it provides a fast well-formedness parser.

To perform data validation, use a validating XmlReader. For more information, see Validating XML Data with XmlReader.

To read XML data from an XmlDocument, use XmlNodeReader.

XmlTextReader throws an XmlException on XML parse errors. After an exception is thrown the state of the reader is not predictable. For example, the reported node type may be different than the actual node type of the current node. Use the ReadState property to check whether a reader is in error state.

For further discussion on the XmlReader classes, see Reading XML with the XmlReader.

Security Considerations

The following are things to consider when using the XmlTextReader class.

Exceptions thrown the XmlTextReader can disclose path information that you do not want bubbled up to the application. Your applications must catch exceptions and process them appropriately.
DTD processing is enabled by default. Disable DTD processing if you are concerned about Denial of Service issues or if you are dealing with untrusted sources. Set the DtdProcessing property to Prohibit to disable DTD processing.

If you have DTD processing enabled, you can use the XmlSecureResolver to restrict the resources that the XmlTextReader can access. You can also design your application so that the XML processing is memory and time constrained. For example, configure time-out limits in your ASP.NET application.
XML data can include references to external resources such as a DTD file. By default external resources are resolved using an XmlUrlResolver object with no user credentials. You can secure this further by doing one of the following:
- Restrict the resources that the XmlTextReader can access by setting the XmlResolver property to an XmlSecureResolver object.
- Do not allow the XmlReader to open any external resources by setting the XmlResolver property to null.
XML data can contain a large number of attributes, namespace declarations, nested elements and so on that require a substantial amount of time to process. To limit the size of the input that is sent to the XmlTextReader, create a custom IStream implementation and supply it the XmlTextReader.
The ReadValueChunk method can be used to handle large streams of data. This method reads a small number of characters at a time instead of allocating a single string for the whole value.
By default general entities are not expanded. General entities are expanded when you call the ResolveEntity method.

Notes to Inheritors

This class has an inheritance demand. Full trust is required to inherit from XmlTextReader. See Inheritance Demands for more information.

Version Information

.NET Framework

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

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Platforms

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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

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.