DOM节点中属性nodeName、nodeType和nodeValue的区别Delphi

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http://msdn.microsoft.com/zh-cn/library/vstudio/hf9hbf87.aspx

<?xml version="1.0"?>
  <books>
    <book>
        <author>Carson</author>
        <price format="dollar">31.95</price>
        <pubdate>05/01/2001</pubdate>
    </book>
    <pubinfo>
        <publisher>MSPress</publisher>
        <state>WA</state>
    </pubinfo>
  </books>

XmlDocument 类（扩展XmlNode）支持用于对整个文档执行操作（例如，将文档加载到内存中或将 XML 保存到文件中）的方法。

XmlNode 和 XmlDocument 都具有性能和可用性增强，并通过方法和属性执行下列操作：

访问和修改 DOM 特定的节点，如元素节点、实体引用节点等。
除检索节点包含的信息（如元素节点中的文本）外，还检索整个节点。

其中的某些特性包括：

唯一没有父级的节点是文档根，因为它是顶级节点，包含了文档本身和文档片段。
以下是可以有子节点的节点类型列表。
- Document
- DocumentFragment
- EntityReference
- Element
- Attribute
XmlDeclaration、Notation、Entity、CDATASection、Text、Comment、ProcessingInstruction 和 DocumentType 节点没有子节点。
处于同一级别、在关系图中由 book 和 pubinfo 节点表示的节点是同级。

属性被视为元素节点的属性，由名称和值对组成。

dollar。

有关更多信息，请参见访问 DOM 中的属性。

http://linder0209.iteye.com/blog/1458823

http://www.css88.com/archives/5017

(一)nodeName 属性含有某个节点的名称。

元素节点的 nodeName 是标签名称

属性节点的 nodeName 是属性名称

文本节点的 nodeName 永远是 #text

文档节点的 nodeName 永远是 #document

注释：nodeName 所包含的 XML 元素的标签名称永远是大写的

nodeName 属性含有某个节点的名称。

元素（element）节点的 nodeName 是标签名称
属性（attribute）节点的 nodeName 是属性名称
文本（text）节点的 nodeName 永远是 #text
文档（document）节点的 nodeName 永远是 #document

(二)nodeValue

对于文本节点，nodeValue 属性包含文本。

对于属性节点，nodeValue 属性包含属性值。

nodeValue 属性对于文档节点 <document> 和元素节点 <element> 是不可用的。

(三)nodeType

nodeType 属性可返回节点的类型。

最重要的节点类型是：

元素类型节点类型

元素element 1

属性attr 2

文本text 3

注释comments 8

文档document 9

http://www.w3schools.com/dom/dom_nodetype.asp

Node Types

The following table lists the different W3C node types, and which node types they may have as children:

Node type	Description	Children
Document	Represents the entire document (the root-node of the DOM tree)	Element (max. one), ProcessingInstruction, Comment, DocumentType
DocumentFragment	Represents a "lightweight" Document object, which can hold a portion of a document	Element, ProcessingInstruction, Comment, Text, CDATASection, EntityReference
DocumentType	Provides an interface to the entities defined for the document	None
ProcessingInstruction	Represents a processing instruction	None
EntityReference	Represents an entity reference	Element, ProcessingInstruction, Comment, Text, CDATASection, EntityReference
Element	Represents an element	Element, Text, Comment, ProcessingInstruction, CDATASection, EntityReference
Attr	Represents an attribute	Text, EntityReference
Text	Represents textual content in an element or attribute	None
CDATASection	Represents a CDATA section in a document (text that will NOT be parsed by a parser)	None
Comment	Represents a comment	None
Entity	Represents an entity	Element, ProcessingInstruction, Comment, Text, CDATASection, EntityReference
Notation	Represents a notation declared in the DTD	None

Node Types - Return Values

The following table lists what the nodeName and the nodeValue properties will return for each node type:

Node type	nodeName returns	nodeValue returns
Document	#document	null
DocumentFragment	#document fragment	null
DocumentType	doctype name	null
EntityReference	entity reference name	null
Element	element name	null
Attr	attribute name	attribute value
ProcessingInstruction	target	content of node
Comment	#comment	comment text
Text	#text	content of node
CDATASection	#cdata-section	content of node
Entity	entity name	null
Notation	notation name	null

NodeTypes - Named Constants

NodeType	Named Constant
1	ELEMENT_NODE
2	ATTRIBUTE_NODE
3	TEXT_NODE
4	CDATA_SECTION_NODE
5	ENTITY_REFERENCE_NODE
6	ENTITY_NODE
7	PROCESSING_INSTRUCTION_NODE
8	COMMENT_NODE
9	DOCUMENT_NODE
10	DOCUMENT_TYPE_NODE
11	DOCUMENT_FRAGMENT_NODE
12	NOTATION_NODE

http://www.w3school.com.cn/xmldom/dom_nodes_nodelist.asp

<bookstore>
  <book category="children">
    <title lang="en">Harry Potter</title>
    <author>J K. Rowling</author>
    <year>2005</year>
    <price>29.99</price>
  </book>
  <book category="cooking">
    <title lang="en">Everyday Italian</title>
    <author>Giada De Laurentiis</author>
    <year>2005</year>
    <price>30.00</price>
  </book>
  <book category="web" cover="paperback">
    <title lang="en">Learning XML</title>
    <author>Erik T. Ray</author>
    <year>2003</year>
    <price>39.95</price>
  </book>
  <book category="web">
    <title lang="en">XQuery Kick Start</title>
    <author>James McGovern</author>
    <author>Per Bothner</author>
    <author>Kurt Cagle</author>
    <author>James Linn</author>
    <author>Vaidyanathan Nagarajan</author>
    <year>2003</year>
    <price>49.99</price>
  </book>
</bookstore>

下面的图像表示 "books.xml" 中 <title> 元素的节点列表：

Xml.XMLIntf.IXMLNode.NodeType

Indicates the type of the node.

Read NodeType to determine the type of the node. The type reflects the way the node is used in the XML document.

TNodeType = (
    ntReserved, 
    ntElement, 
    ntAttribute, 
    ntText, 
    ntCData,
    ntEntityRef, 
    ntEntity, 
    ntProcessingInstr, 
    ntComment, 
    ntDocument,
    ntDocType, 
    ntDocFragment, 
    ntNotation);

Xml.XMLIntf.IXMLNode.NodeName

Indicates the node name.

NodeName is the name of the underlying DOM node.

The node's name depends on the type of the node, as indicated in the following table:

NodeType	NodeName
ntAttribute	The attribute name
ntElement	The tag name
ntText	'#text'
ntCData	'#cdata-section'
ntEntityRef	The name of the entity reference.
ntEntity	The entity name
ntProcessingInstr	the target of the processing instruction
ntComment	'#comment'
ntDocument	'#document'
ntDocType	The document type name
ntDocFragment	'#document-fragment'
ntNotation	The notation name

Xml.XMLIntf.IXMLNode.NodeValue

Specifies the value of this node.

Use NodeValue to get or set the value of the node. The meaning of a node's value depends on the type of the node, as indicated in the following table:

NodeType	Value
ntAttribute	The attribute value
ntElement	If the element contains only text, this is that text value. Otherwise, trying to read or set NodeValue causes an exception.
ntText	The text
ntCData	The content of the CDATA section.
ntProcessingInstr	The content of the processing instruction except for the target.
ntComment	The value (text) of the comment.

Xml.XMLIntf.IXMLNode.IsTextElement

Indicates whether the node has a single text value.

Read IsTextElement to determine whether this node represents a single text value. For example, if the node represents the following:

<Title> Understanding XML </Title>

IsTextElement is true, because the node represents a tagged element and the text that is its value.

Note:

In the underlying DOM implementation, nodes for which IsTextElement is true are element nodes that have a single child node that is a text node.

IXMLNode flattens this out so that you can use the element node to work with the text value (through the Text property),

rather than requiring you to use a separate node for the text value.