There are two ways C can read XML

XML role

 ,  ,  , XML, XML, XML, XML, XML, Web, XML1, Web, Web, XML, XML, Web, Web, Web, Web, Web, Web The data transfer for Internet, I think, is the most attractive part of XML for us programmers!

Our topic today is not about the benefits of XML, but about how to use XML in C#. Let's take a look at some of the basics of using the program to access XML.

Two models of access:

      access in your application and operating XML file 1, there are two kinds of models, respectively, is to use DOM (document object model (dom), and flow model, the benefits of using DOM is that it allows editing and updating XML documents, can random access data in a document, you can use XPath query, however, DOM drawback is that it needs to be one of loading the entire document into memory, for a large document, which can cause resource problems. The flow model solves this problem well, because its access to the XML file is based on the concept of a stream, that is, only the current node in memory at any given time, but it also has its drawbacks, it is read-only, only forward, and cannot perform backward navigation in the document. Although each has its own advantages and disadvantages, we can also use both in the program to achieve the advantages and disadvantages of complementary well, hehe

1. DOM document object model operations

using System.Xml;
XmlDocument xml=new XmlDocument();// Initialize the 1 a xml The instance 
xml.Load(path);// Import specified xml file 
xml.Load(HttpContext.Current.Server.MapPath("~/file/bookstore.xml"));XmlNode root=xml.SelectSingleNode("/root");// The specified 1 A node 
XmlNodeList childlist=root.ChildNodes;// Gets all direct child nodes under a node 
XmlNodeList nodelist=xml.SelectNodes("/Root/News");// Gets a collection of sibling nodes of the same name string id=node.Attributes["id"].Value;// Gets the specified property value for the specified node 
string content=node.InnerText;// Gets the text in the specified node 
root.HasChildNodes;// Determine whether there are child nodes under this node 

1. Properties of class XmlDocument

The properties and descriptions of the       XmlDocument class are shown in the following table.

attribute

instructions

Attributes

The collection of properties of the current node

BaseURI

Base URI for the current node

ChildNodes

All child nodes of a node

DocumentElement

The root of the document

DocumentType

Node declared by DOCTYPE

FirstChild

The first child of the node

HasChildNodes

Whether there are any child nodes

Implementation

Gets the XmlImplementation object for the current document

InnerText

The node contains all the text content

InnerXml

All XML contents contained by the node

IsReadOnly

Is the current node read-only

Item

Gets the specified child element

LastChild

The last one is a child node

LocalName

Gets the local name of the node

Name

Gets the qualified name of the node

NamespaceURI

Gets the namespace URI for the node

NameTable

Gets XmlNameTable associated with this implementation

NextSibling

Gets the node immediately following that node

NodeType

Gets the type of the current node

OuterXml

Gets a tag that represents this node and all its children

OwnerDocument

Gets XmlDocument to which the current node belongs

ParentNode

Gets the parent of the node (for nodes that can have a parent)

Prefix

Gets or sets the namespace prefix for the node

PreserveWhitespace

Gets or sets a value indicating whether to leave white space in the element content

PreviousSibling

Gets the node immediately before the node

SchemaInfo

Returns the post-schema validation information set for the node (PSVI)

Schemas

Gets or sets the XmlSchemaSet object associated with this XmlDocument

Value

Gets or sets the value of the node

XmlResolver

Set XmlResolver for parsing external resources

  2. Methods of class XmlDocument

The methods and instructions for the     XmlDocument class are shown in the following table.

methods

instructions

AppendChild

Adds the specified node to the end of the list of child nodes of the node

CreateAttribute

Creates XmlAttribute with the specified name

CreateCDataSection

Creates XmlCDataSection that contains the specified data

CreateComment

Creates XmlComment that contains the specified data

CreateDocumentFragment

Create XmlDocumentFragment

CreateDocumentType

Returns the new XmlDocumentType object

CreateElement

Create XmlElement

CreateEntityReference

Creates XmlEntityReference with the specified name

CreateNavigator

Create a new XPathNavigator object to navigate the document

CreateNode

Create XmlNode

CreateProcessingInstruction

Create an XmlProcessingInstruction with the specified name and data

CreateSignificantWhitespace

Create an XmlSignificantWhitespace node

CreateTextNode

Creates XmlText with the specified text

CreateWhitespace

Create one XmlWhitespace node

CreateXmlDeclaration

Creates an XmlDeclaration node with the specified value

GetElementById

Gets XmlElement with the specified ID

GetElementsByTagName

Returns an   XmlNodeList   containing a list of all elements that match the specified name

GetNamespaceOfPrefix  

Finds the xmlns declaration closest to the given prefix in the current node range and returns the namespace URI in the declaration

GetPrefixOfNamespace  

Finds the xmlns declaration closest to the given namespace URI within the current node range and returns the prefix defined in the declaration

GetType

Gets the Type of the current instance

ImportNode

Import the node from another document into the current document

InsertAfter

Inserts the specified node immediately after the specified reference node

InsertBefore

Inserts the specified node immediately before the specified reference node

Load

Loads the specified XML data

LoadXml

Loads the XML document from the specified string

Normalize  

Convert all XmlText nodes to "normal" form

PrependChild  

Adds the specified node to the beginning of the list of child nodes for that node

ReadNode

Create an XmlNode object based on the information in   XmlReader  . The reader must be positioned on a node or property

RemoveAll  

Removes all child nodes and/or properties of the current node

RemoveChild  

Removes the specified child node

ReplaceChild  

Replace the old node with the new one

Save

Save the XML document to the specified location

SelectNodes  

Select the list of nodes that match the XPath expression

SelectSingleNode  

Select the first XmlNode to match the XPath expression

Supports  

Test whether the DOM implementation implements specific functionality

Validate

Verify that XmlDocument is not the XML schema definition language (XSD) schema included in the   Schemas   property.

WriteContentTo

Save all child levels of the XmlDocument node to the specified   XmlWriter  

WriteTo

Save the XmlDocument node to the specified XmlWriter

  introduces the common methods below.

  (1) Load method

The   method can import XML data from an XML file specified by a string, or from a stream object, an TextReader object, or an XmlReader object.

  (2) LoadXml method

The   method performs the import of XML data from a specific XML file. By default, the LoadXml method retains neither whitespace nor meaningful whitespace. This method does not perform DTD or schema validation.

  (3) Save method

  this method saves XML data to an XML file or imports XML data into a stream object, an TextReader object, and an XmlReader object.

  3. Events of the XmlDocument class

The events and instructions for the       XmlDocument class are shown in the following table.

                                    XmlDocument events and instructions

The event

instructions

NodeChanged

Occurs when the Value belonging to the node of the document has been changed

NodeChanging

Occurs when the Value belonging to the node of the document is about to be changed

NodeInserted

Occurs when a node belonging to the document has been inserted into another node

NodeInserting

Occurs when a node belonging to the document will be inserted into another node

NodeRemoved

Occurs when a node belonging to the document has been removed from its parent

NodeRemoving

Occurs when a node belonging to the document is to be removed from the document

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