LINQ - XML

LINQ - XML 首页 / LinQ入门教程 / LINQ - XML

LINQ to XML提供了对所有LINQ功能(如标准查询运算符,编程接口等)的轻松访问。集成在.NET框架中的LINQ to XML还充分利用了.NET框架功能,如调试,编译时检查,强类型化还有更多要说的。

LINQ XML

在使用LINQ to XML时,将XML文档加载到内存很容易,并且查询和文档修改也更加容易,也可以将内存中存在的XML文档保存到磁盘并进行序列化,它消除了开发人员学习稍微复杂的XML查询语言的需要。

LINQ to XML在System.Xml.Linq命名空间中具有强大的功能,它具有使用XML所需的全部19个必需类,这些类是以下类。

无涯教程网

  • XAttribute
  • XCData
  • XComment
  • XContainer
  • XDeclaration
  • XDocument
  • XDocumentType
  • XElement
  • XName
  • XNamespace
  • XNode
  • XNodeDocumentOrderComparer
  • XNodeEqualityComparer
  • XObject
  • XObjectChange
  • XObjectChangeEventArgs
  • XObjectEventHandler
  • XProcessingInstruction
  • XText

读取XML文件

C#

链接:https://www.learnfk.comhttps://www.learnfk.com/linq/linq-xml.html

来源:LearnFk无涯教程网

using System;
using System.Collections.Generic;
using System.Linq;
using System.Xml.Linq;

namespace LINQtoXML {
   class ExampleOfXML {
      static void Main(string[] args) {
      
         string myXML = @"<Departments>
                       <Department>Account</Department>
                       <Department>Sales</Department>
                       <Department>Pre-Sales</Department>
                       <Department>Marketing</Department>
                       </Departments>";

         XDocument xdoc = new XDocument();
         xdoc = XDocument.Parse(myXML);

         var result = xdoc.Element("Departments").Descendants();

         foreach (XElement item in result) {
            Console.WriteLine("Department Name - " + item.Value);
         }

         Console.WriteLine("\nPress any key to continue.");
         Console.ReadKey();
      }
   }
}

VB

Imports System.Collections.Generic
Imports System.Linq
Imports System.Xml.Linq

Module Module1

   Sub Main(ByVal args As String())
   
      Dim myXML As String = "<Departments>" & vbCr & vbLf & 
                           "<Department>Account</Department>" & vbCr & vbLf & 
                           "<Department>Sales</Department>" & vbCr & vbLf & 
                           "<Department>Pre-Sales</Department>" & vbCr & vbLf & 
                           "<Department>Marketing</Department>" & vbCr & vbLf & 
                           "</Departments>"

      Dim xdoc As New XDocument()
      xdoc = XDocument.Parse(myXML)

      Dim result = xdoc.Element("Departments").Descendants()

      For Each item As XElement In result
         Console.WriteLine("Department Name - " + item.Value)
      Next

      Console.WriteLine(vbLf & "Press any key to continue.")
      Console.ReadKey()
	  
   End Sub
   
End Module

编译并执行以上C#或VB的代码时,将产生以下输出-

Department Name - Account
Department Name - Sales
Department Name - Pre-Sales
Department Name - Marketing

Press any key to continue. 

添加新节点

C#

链接:https://www.learnfk.comhttps://www.learnfk.com/linq/linq-xml.html

来源:LearnFk无涯教程网

using System;
using System.Collections.Generic;
using System.Linq;
using System.Xml.Linq;

namespace LINQtoXML {
   class ExampleOfXML {
      static void Main(string[] args) {
      
         string myXML = @"<Departments>
                       <Department>Account</Department>
                       <Department>Sales</Department>
                       <Department>Pre-Sales</Department>
                       <Department>Marketing</Department>
                       </Departments>";

         XDocument xdoc = new XDocument();
         xdoc = XDocument.Parse(myXML);

         //Add new Element
         xdoc.Element("Departments").Add(new XElement("Department", "Finance"));

         //Add new Element at First
         xdoc.Element("Departments").AddFirst(new XElement("Department", "Support"));

         var result = xdoc.Element("Departments").Descendants();

         foreach (XElement item in result) {
            Console.WriteLine("Department Name - " + item.Value);
         }

         Console.WriteLine("\nPress any key to continue.");
         Console.ReadKey();
      }
   }
}

VB

Imports System.Collections.Generic
Imports System.Linq
Imports System.Xml.Linq

Module Module1

   Sub Main(ByVal args As String())
   
      Dim myXML As String = "<Departments>" & vbCr & vbLf & 
     	                   "<Department>Account</Department>" & vbCr & vbLf & 
     	                   "<Department>Sales</Department>" & vbCr & vbLf & 
     	                   "<Department>Pre-Sales</Department>" & vbCr & vbLf & 
     	                   "<Department>Marketing</Department>" & vbCr & vbLf & 
     	                   "</Departments>"

      Dim xdoc As New XDocument()
      xdoc = XDocument.Parse(myXML)

      xdoc.Element("Departments").Add(New XElement("Department", "Finance"))
     
      xdoc.Element("Departments").AddFirst(New XElement("Department", "Support"))

      Dim result = xdoc.Element("Departments").Descendants()

      For Each item As XElement In result
         Console.WriteLine("Department Name - " + item.Value)
      Next

      Console.WriteLine(vbLf & "Press any key to continue.")
      Console.ReadKey()
	  
   End Sub
   
End Module

编译并执行以上C#或VB的代码时,将产生以下输出-

Department Name - Support
Department Name - Account
Department Name - Sales
Department Name - Pre-Sales
Department Name - Marketing
Department Name - Finance

Press any key to continue.

删除特定节点

C#

链接:https://www.learnfk.comhttps://www.learnfk.com/linq/linq-xml.html

来源:LearnFk无涯教程网

using System;
using System.Collections.Generic;
using System.Linq;
using System.Xml.Linq;

namespace LINQtoXML {
   class ExampleOfXML {
      static void Main(string[] args) {
      
         string myXML = @"<Departments>
                       <Department>Support</Department>
                       <Department>Account</Department>
                       <Department>Sales</Department>
                       <Department>Pre-Sales</Department>
                       <Department>Marketing</Department>
                       <Department>Finance</Department>
                       </Departments>";

         XDocument xdoc = new XDocument();
         xdoc = XDocument.Parse(myXML);

         //Remove Sales Department
         xdoc.Descendants().Where(s =>s.Value == "Sales").Remove(); 

         var result = xdoc.Element("Departments").Descendants();

         foreach (XElement item in result) {
            Console.WriteLine("Department Name - " + item.Value);
         }

         Console.WriteLine("\nPress any key to continue.");
         Console.ReadKey();
      }
   }
}

VB

Imports System.Collections.Generic
Imports System.Linq
Imports System.Xml.Linq

Module Module1

   Sub Main(args As String())
   
      Dim myXML As String = "<Departments>" & vbCr & vbLf & 
     	                   "<Department>Support</Department>" & vbCr & vbLf & 
     	                   "<Department>Account</Department>" & vbCr & vbLf & 
     	                   "<Department>Sales</Department>" & vbCr & vbLf & 
     	                   "<Department>Pre-Sales</Department>" & vbCr & vbLf & 
     	                   "<Department>Marketing</Department>" & vbCr & vbLf & 
     	                   "<Department>Finance</Department>" & vbCr & vbLf & 
                           "</Departments>"

      Dim xdoc As New XDocument()
      xdoc = XDocument.Parse(myXML)
     
      xdoc.Descendants().Where(Function(s) s.Value = "Sales").Remove()

      Dim result = xdoc.Element("Departments").Descendants()

      For Each item As XElement In result
         Console.WriteLine("Department Name - " + item.Value)
      Next

      Console.WriteLine(vbLf & "Press any key to continue.")
      Console.ReadKey()
	  
   End Sub
   
End Module

编译并执行以上C#或VB的代码时,将产生以下输出-

Department Name - Support
Department Name - Account
Department Name - Pre-Sales
Department Name - Marketing
Department Name - Finance

Press any key to continue. 

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