Xpath: uses path expressions to select nodes / node set XML document.
- path expressions: from one node to another node or XML
The step of writing to a group of nodes "/" separated
Each step is composed of three components:
Axis test node test node descriptor
About Xpath:
(1) use path expressions to navigate in XML documents
(2) contains a standard library
(3) is a major element in XSLT
(4) is a W3C standard
Details:
1, Node: namespace element attributes text annotation and document processing instruction (root) node
2, the syntax:
1> Select node: nodename byte select all points of this node
/ Select from the root node
// select a document from the current node in the node match regardless of their location
. Select the current node
.. select the parent node of the current node
@ Select Properties
3, predicate (Predicates): used to find a particular node or a node containing a specific value by [] represents
[1]
[last()]
[last()-1]
[Position () <3] to select two top
[@Lang] Select a node attribute named lang
// title [@ lang = 'eng'] Select all title elements and these elements have a lang attribute value eng
Select the unknown node
Wildcards can be used to select xpath unknown XML element
* Matches any element node
@ * Matches any attribute node
node () matches any type node
Example:
// title [@ *] select all the title elements with attributes
Select several nodes
Use "|" Operator
Operators:! + - * | div (division) = = or and mod (modulo)
Select nodes;
IE: XmlDoc.selectNodes(xpath);
Other: XmlDoc.evaluate (xpath, xmlDoc, null, XpathResult.ANTTYPE, NULL);