C # uses XPath to find XML node information

Source: Internet
Author: User
Tags xml example xpath

XPath is a powerful, but also relatively complex technology, it is best to go to the blog Park to find some professional posts to look at, here are some simple XPath syntax and an example, to provide you with reference.

XML Example:

<?XML version= "1.0" encoding= "Utf-8"?><Roles>  <roleOrder= "1">    <Roleid>1</Roleid>    <RoleName>General users</RoleName>  </role>  <roleOrder= "3">    <Roleid>2</Roleid>    <RoleName>Test user</RoleName>  </role>  <roleOrder= "2">    <Roleid>3</Roleid>    <RoleName>Center Administrator</RoleName>  </role>  <roleOrder= "4">    <Roleid>4</Roleid>    <RoleName>System administrator</RoleName>  </role></Roles>

Description: If the beginning of the XPath is a slash (/) represents this is the absolute path. If the beginning is a two slash (//) indicates that all conforming elements in the file will be selected, even at different levels in the tree

1. Select the rolename of the first role

Example:/roles/role[1]/rolename Description: The subscript in XML is starting with 1

2. Select the node for the role of attribute order= ' 2 '

Example:/roles/role[@order = ' 2 ') Description: @order represents a property

3. Select the value of the order of the first role


Summary: The above is the XPath syntax, but how to use it in C #, the code is as follows:

New XmlDocument ();  // instantiate a XmlDocument XML. Load ("app.xml");        // to load an XML document from a path // The index in XML starts at 1 XmlNode node=xml. selectSingleNode ("/roles/role[1]/@order");    Depending on the XPath that returns a specific node, if there are multiple nodes that match, the first node is returned, and the selectnodes () term obtains a collection of multiple nodes MessageBox.Show (node. InnerText);    // read the information about the node

C # uses XPath to find XML node information

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