C# Linq to XML - 更新/更改 XML 文档的节点
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时间：2020-08-03 23:31:24 来源:igfitidea点击:
Linq to XML - update/alter the nodes of an XML Document
提问by
I've got 2 Questions:
我有2个问题：
1. I've sarted working around with Linq to XML and i'm wondering if it is possible to change an XML document via Linq. I mean, is there someting like
1. 我已经开始使用 Linq to XML，我想知道是否可以通过 Linq 更改 XML 文档。我的意思是，有没有像
XDocument xmlDoc = XDocument.Load("sample.xml");
update item in xmlDoc.Descendants("item")
where (int)item .Attribute("id") == id
...
2. I already know how to create and add a new XMLElement by simply using
2. 我已经知道如何通过简单地使用来创建和添加新的 XMLElement
xmlDoc.Element("items").Add(new XElement(......);
but how can I remove a single entry?
但是如何删除单个条目？
XML sample data:
XML 示例数据：
<items>
<item id="1" name="sample1" info="sample1 info" web="" />
<item id="2" name="sample2" info="sample2 info" web="" />
</itmes>
回答by Robert Rossney
Is this what you have in mind?
这是你的想法吗？
using System;
using System.Linq;
using System.Xml.Linq;
static void Main(string[] args)
{
string xml = @"<data><record id='1'/><record id='2'/><record id='3'/></data>";
StringReader sr = new StringReader(xml);
XDocument d = XDocument.Load(sr);
// the verbose way, if you will be removing many elements (though in
// this case, we're only removing one)
var list = from XElement e in d.Descendants("record")
where e.Attribute("id").Value == "2"
select e;
// convert the list to an array so that we're not modifying the
// collection that we're iterating over
foreach (XElement e in list.ToArray())
{
e.Remove();
}
// the concise way, which only works if you're removing a single element
// (and will blow up if the element isn't found)
d.Descendants("record").Where(x => x.Attribute("id").Value == "3").Single().Remove();
XmlWriter xw = XmlWriter.Create(Console.Out);
d.WriteTo(xw);
xw.Flush();
Console.ReadLine();
}
回答by Robert Rossney
thank you for your answer. everything works fine.
谢谢您的回答。一切正常。
just as completition to my questions the code below shows how to modify a single entry:
就像完成我的问题一样，下面的代码显示了如何修改单个条目：
string xml = @"<data><record id='1' info='sample Info'/><record id='2' info='sample Info'/><record id='3' info='sample Info'/></data>";
StringReader sr = new StringReader(xml);
XDocument d = XDocument.Load(sr);
d.Descendants("record").Where(x => x.Attribute("id").Value == "2").Single().SetAttributeValue("info", "new sample info");
回答by Ajay JIlakara
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Xml.Linq;
namespace LinqToXmlTest
{
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void ReadXml()
{
XDocument xdocument = XDocument.Load(Server.MapPath("People.xml"));
var persons = from person in xdocument.Descendants("Person")
select new
{
Name = person.Element("Name").Value,
City = person.Element("City").Value,
Age = person.Element("Age").Value
};
litResults.Text = "";
foreach (var person in persons)
{
litResults.Text = litResults.Text + "Name: " + person.Name + "<br/>";
litResults.Text = litResults.Text + "City: " + person.City + "<br/>";
litResults.Text = litResults.Text + "Age: " + person.Age + "<br/><br/>";
}
if (litResults.Text == "")
litResults.Text = "No Results...";
}
protected void butAdd_Click(object sender, EventArgs e)
{
try
{
if (txtName.Text == "" || txtCity.Text == "" || txtAge.Text == "")
{
lblStatus.ForeColor = System.Drawing.Color.Red;
lblStatus.Text = "Please Complete the form";
}
else
{
XDocument xdocumnet = XDocument.Load(Server.MapPath("People.xml"));
xdocumnet.Element("Persons").Add(new XElement("Person",
new XElement("Name", txtName.Text),
new XElement("City", txtCity.Text),
new XElement("Age", txtAge.Text)));
xdocumnet.Save(Server.MapPath("People.xml"));
lblStatus.ForeColor = System.Drawing.Color.Green;
lblStatus.Text = "Data Successfully loaded to xml file";
txtName.Text = "";
txtCity.Text = "";
txtAge.Text = "";
ReadXml();
}
}
catch
{
lblStatus.ForeColor = System.Drawing.Color.Red;
lblStatus.Text = "Sorry unable to precess request.Please try again";
}
}
protected void butRead_Click(object sender, EventArgs e)
{
ReadXml();
lblStatus.Text = "";
}
protected void btnUpdate_Click(object sender, EventArgs e)
{
try
{
if (txtName.Text == "" || txtCity.Text == "" || txtAge.Text == "")
{
lblStatus.ForeColor = System.Drawing.Color.Red;
lblStatus.Text = "Please enter all details in the form";
}
else
{
XDocument xdocument = XDocument.Load(Server.MapPath("People.xml"));
var persondata = (from person in xdocument.Descendants("Person")
where person.Element("Name").Value.Equals(txtName.Text)
select person).Single();
persondata.Element("City").Value = txtCity.Text;
persondata.Element("Age").Value = txtAge.Text;
xdocument.Save(Server.MapPath("People.xml"));
lblStatus.ForeColor = System.Drawing.Color.Green;
lblStatus.Text = "The data updated successfully";
ReadXml();
}
}
catch(Exception ex)
{
lblStatus.ForeColor = System.Drawing.Color.Red;
lblStatus.Text = ex.Message;
}
}
protected void btnDelete_Click(object sender, EventArgs e)
{
try
{
if (txtName.Text == "")
{
lblStatus.ForeColor = System.Drawing.Color.Red;
lblStatus.Text = "Please enter the name of the person to delete...";
}
else
{
XDocument xdocument = XDocument.Load(Server.MapPath("People.xml"));
var persondata = (from person in xdocument.Descendants("Person")
where person.Element("Name").Value.Equals(txtName.Text)
select person).Single();
persondata.Remove();
xdocument.Save(Server.MapPath("People.xml"));
lblStatus.ForeColor = System.Drawing.Color.Green;
lblStatus.Text = "The data deleted successfully...";
txtName.Text = "";
txtCity.Text = "";
txtAge.Text = "";
ReadXml();
}
}
catch (Exception ex)
{
lblStatus.ForeColor = System.Drawing.Color.Red;
lblStatus.Text = ex.Message;
}
}
}
}
回答by karthikeyan
static void Main(string[] args)
{
//XmlDocument doc = new XmlDocument();
//XmlElement newBook=doc.CreateElement("BookParticipant");
//newBook.SetAttribute("Author");
//Using Functional Construction to Create an XML Schema
XElement xBookParticipant = new XElement("BookParticipant",
new XElement("FirstName", "Joe"),
new XElement("LastName", "Rattz"));
Console.WriteLine(xBookParticipant.ToString());
//Creates the Same XML Tree as Listing 6-1 but with Far Less Code
XElement xBookParticipants = new XElement("BookParticipants",
new XElement("BookParticipant",
new XAttribute("type", "Author"),
new XElement("FirstName", "Joe"),
new XElement("LastName", "Rattz")),
new XElement("BookParticipant",
new XAttribute("type", "Editor"),
new XElement("FirstName", "Ewan"),
new XElement("LastName", "Buckingham")));
Console.WriteLine(xBookParticipants.ToString());
//-- Disadvatages of XML document
//System.Xml.XmlElement xmlBookParticipant = new System.Xml.XmlElement("BookParticipant");
XElement xeBookParticipant = new XElement("BookParticipant");
XDocument xDocument = new XDocument(new XElement("BookParticipants",
new XElement("BookParticipant",
new XAttribute("type", "Author"),
new XElement("FirstName", "Joe"),
new XElement("LastName", "Rattz"))));
Console.WriteLine(xDocument.ToString());
//--Calling the ToString Method on an Element Produces the XML Tree
XElement name = new XElement("Name", "Joe");
Console.WriteLine(name.ToString());
//--Console.WriteLine Implicitly Calling the ToString Method on an Element to Produce an XML Tree
XElement name1 = new XElement("Person",
new XElement("FirstName", "Joe"),
new XElement("LastName", "Rattz"));
Console.WriteLine(name1);
//-- Casting an Element to Its Value's Data Type Outputs the Value
Console.WriteLine(name);
Console.WriteLine((string)name);
//--Different Node Value Types Retrieved via Casting to the Node Value's Type
XElement count = new XElement("Count", 12);
Console.WriteLine(count);
Console.WriteLine((int)count);
XElement smoker = new XElement("Smoker", false);
Console.WriteLine(smoker);
Console.WriteLine((bool)smoker);
XElement pi = new XElement("Pi", 3.1415926535);
Console.WriteLine(pi);
Console.WriteLine((double)pi);
DeferredQryProblem();
GenerateXMlFromLinqQry();
}
private static void DeferredQryProblem()
{
XDocument xDocument = new XDocument(
new XElement("BookParticipants",
new XElement("BookParticipant",
new XAttribute("type", "Author"),
new XElement("FirstName", "Joe"),
new XElement("LastName", "Rattz")),
new XElement("BookParticipant",
new XAttribute("type", "Editor"),
new XElement("FirstName", "Ewan"),
new XElement("LastName", "Buckingham"))));
IEnumerable<XElement> elements =
xDocument.Element("BookParticipants").Elements("BookParticipant");
foreach (XElement element in elements)
{
Console.WriteLine("Source element: {0} : value = {1}",
element.Name, element.Value);
}
foreach (XElement element in elements)
{
Console.WriteLine("Removing {0} = {1} ...", element.Name, element.Value);
element.Remove();
}
Console.WriteLine(xDocument);
foreach (XElement element in elements)
{
Console.WriteLine("Source element: {0} : value = {1}",
element.Name, element.Value);
}
foreach (XElement element in elements.ToArray())
{
Console.WriteLine("Removing {0} = {1} ...", element.Name, element.Value);
element.Remove();
}
Console.WriteLine(xDocument);
}
//-- Creating an Attribute and Adding It to Its Element
private static void CreatingAttribute()
{
XElement xBookParticipant = new XElement("BookParticipant", new XAttribute("type", "Author"));
Console.WriteLine(xBookParticipant);
}
//--Creating a Comment with Functional Construction
private static void CreatingComment()
{
XElement xBookParticipant = new XElement("BookParticipant",
new XComment("This person is retired."));
Console.WriteLine(xBookParticipant);
}
//--Creating a Declaration with Functional Construction
private static void CreateXmlDeclaration()
{
XDocument xDocument = new XDocument(new XDeclaration("1.0", "UTF-8", "yes"),
new XElement("BookParticipant"));
Console.WriteLine(xDocument);
}
private static void GenerateXMlFromLinqQry()
{
BookParticipant[] bookParticipants = new[] {new BookParticipant {FirstName = "Joe", LastName = "Rattz",
ParticipantType = ParticipantTypes.Author},
new BookParticipant {FirstName = "Ewan", LastName = "Buckingham",
ParticipantType = ParticipantTypes.Editor}
};
XElement xBookParticipants =
new XElement("BookParticipants",
bookParticipants.Select(p =>
new XElement("BookParticipant",
new XAttribute("type", p.ParticipantType),
new XElement("FirstName", p.FirstName),
new XElement("LastName", p.LastName))));
Console.WriteLine(xBookParticipants);
}
//-- Obtaining Elements Without Reaching
private static void WithoutReaching()
{
XDocument xDocument = new XDocument(new XElement("BookParticipants",
new XElement("BookParticipant",
new XAttribute("type", "Author"),
new XElement("FirstName", "Joe"),
new XElement("LastName", "Rattz")),
new XElement("BookParticipant",
new XAttribute("type", "Editor"),
new XElement("FirstName", "Ewan"),
new XElement("LastName", "Buckingham"))));
IEnumerable<XElement> elements = xDocument.Descendants("BookParticipant");
foreach (XElement element in elements)
{
Console.WriteLine("Element: {0} : value = {1}",
element.Name, element.Value);
}
IEnumerable<XElement> elements1 = xDocument.Descendants("BookParticipant")
.Where(e => ((string)e.Element("FirstName")) == "Ewan");
foreach (XElement element1 in elements1)
{
Console.WriteLine("Element: {0} : value = {1}",
element1.Name, element1.Value);
}
}
回答by karthikeyan
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Xml.Linq; //using System.Xml;
使用系统；使用 System.Collections.Generic; 使用 System.Linq；使用 System.Text; 使用 System.Xml.Linq; //使用 System.Xml;
namespace XMLtoLinqApp { class Program { static void Main(string[] args) {
命名空间 XMLtoLinqApp { class Program { static void Main(string[] args) {
//XmlDocument doc = new XmlDocument();
//XmlElement newBook=doc.CreateElement("BookParticipant");
//newBook.SetAttribute("Author");
//Using Functional Construction to Create an XML Schema
XElement xBookParticipant = new XElement("BookParticipant",
new XElement("FirstName", "Joe"),
new XElement("LastName", "Rattz"));
Console.WriteLine(xBookParticipant.ToString());
//Creates the Same XML Tree as Listing 6-1 but with Far Less Code
XElement xBookParticipants = new XElement("BookParticipants",
new XElement("BookParticipant",
new XAttribute("type", "Author"),
new XElement("FirstName", "Joe"),
new XElement("LastName", "Rattz")),
new XElement("BookParticipant",
new XAttribute("type", "Editor"),
new XElement("FirstName", "Ewan"),
new XElement("LastName", "Buckingham")));
Console.WriteLine(xBookParticipants.ToString());
//-- Disadvatages of XML document
//System.Xml.XmlElement xmlBookParticipant = new System.Xml.XmlElement("BookParticipant");
XElement xeBookParticipant = new XElement("BookParticipant");
XDocument xDocument = new XDocument(new XElement("BookParticipants",
new XElement("BookParticipant",
new XAttribute("type", "Author"),
new XElement("FirstName", "Joe"),
new XElement("LastName", "Rattz"))));
Console.WriteLine(xDocument.ToString());
//--Calling the ToString Method on an Element Produces the XML Tree
XElement name = new XElement("Name", "Joe");
Console.WriteLine(name.ToString());
//--Console.WriteLine Implicitly Calling the ToString Method on an Element to Produce an XML Tree
XElement name1 = new XElement("Person",
new XElement("FirstName", "Joe"),
new XElement("LastName", "Rattz"));
Console.WriteLine(name1);
//-- Casting an Element to Its Value's Data Type Outputs the Value
Console.WriteLine(name);
Console.WriteLine((string)name);
//--Different Node Value Types Retrieved via Casting to the Node Value's Type
XElement count = new XElement("Count", 12);
Console.WriteLine(count);
Console.WriteLine((int)count);
XElement smoker = new XElement("Smoker", false);
Console.WriteLine(smoker);
Console.WriteLine((bool)smoker);
XElement pi = new XElement("Pi", 3.1415926535);
Console.WriteLine(pi);
Console.WriteLine((double)pi);
DeferredQryProblem();
GenerateXMlFromLinqQry();
WithoutReaching();
Ancestors();
AncestorsAndSelf();
SortSample();
FindElementwithSpecificChild();
}
private static void DeferredQryProblem()
{
XDocument xDocument = new XDocument(
new XElement("BookParticipants",
new XElement("BookParticipant",
new XAttribute("type", "Author"),
new XElement("FirstName", "Joe"),
new XElement("LastName", "Rattz")),
new XElement("BookParticipant",
new XAttribute("type", "Editor"),
new XElement("FirstName", "Ewan"),
new XElement("LastName", "Buckingham"))));
IEnumerable<XElement> elements =
xDocument.Element("BookParticipants").Elements("BookParticipant");
foreach (XElement element in elements)
{
Console.WriteLine("Source element: {0} : value = {1}",
element.Name, element.Value);
}
foreach (XElement element in elements)
{
Console.WriteLine("Removing {0} = {1} ...", element.Name, element.Value);
element.Remove();
}
Console.WriteLine(xDocument);
foreach (XElement element in elements)
{
Console.WriteLine("Source element: {0} : value = {1}",
element.Name, element.Value);
}
foreach (XElement element in elements.ToArray())
{
Console.WriteLine("Removing {0} = {1} ...", element.Name, element.Value);
element.Remove();
}
Console.WriteLine(xDocument);
}
//-- Creating an Attribute and Adding It to Its Element
private static void CreatingAttribute()
{
XElement xBookParticipant = new XElement("BookParticipant", new XAttribute("type", "Author"));
Console.WriteLine(xBookParticipant);
}
//--Creating a Comment with Functional Construction
private static void CreatingComment()
{
XElement xBookParticipant = new XElement("BookParticipant",
new XComment("This person is retired."));
Console.WriteLine(xBookParticipant);
}
//--Creating a Declaration with Functional Construction
private static void CreateXmlDeclaration()
{
XDocument xDocument = new XDocument(new XDeclaration("1.0", "UTF-8", "yes"),
new XElement("BookParticipant")); Console.WriteLine(xDocument); }
new XElement("BookParticipant")); Console.WriteLine(xDocument); }
private static void GenerateXMlFromLinqQry()
{
BookParticipant[] bookParticipants = new[] {new BookParticipant {FirstName = "Joe", LastName = "Rattz",
ParticipantType = ParticipantTypes.Author},
new BookParticipant {FirstName = "Ewan", LastName = "Buckingham",
ParticipantType = ParticipantTypes.Editor}
};
XElement xBookParticipants =
new XElement("BookParticipants",
bookParticipants.Select(p =>
new XElement("BookParticipant",
new XAttribute("type", p.ParticipantType),
new XElement("FirstName", p.FirstName),
new XElement("LastName", p.LastName))));
Console.WriteLine(xBookParticipants);
}
//-- Obtaining Elements Without Reaching
private static void WithoutReaching()
{
XDocument xDocument = new XDocument(new XElement("BookParticipants",
new XElement("BookParticipant",
new XAttribute("type", "Author"),
new XElement("FirstName", "Joe"),
new XElement("LastName", "Rattz")),
new XElement("BookParticipant",
new XAttribute("type", "Editor"),
new XElement("FirstName", "Ewan"),
new XElement("LastName", "Buckingham"))));
//-- Simple Descendants
IEnumerable<XElement> elements = xDocument.Descendants("BookParticipant");
foreach (XElement element in elements)
{
Console.WriteLine("Element: {0} : value = {1}",
element.Name, element.Value);
}
//-- Descendants with Where Clause
IEnumerable<XElement> elements1 = xDocument.Descendants("BookParticipant")
.Where(e => ((string)e.Element("FirstName")) == "Ewan");
foreach (XElement element1 in elements1)
{
Console.WriteLine("Element: {0} : value = {1}",
element1.Name, element1.Value);
}
}
//-- Ancestors Prototype
private static void Ancestors()
{
XDocument xDocument = new XDocument(new XElement("BookParticipants",
new XElement("BookParticipant",
new XAttribute("type", "Author"),
new XElement("FirstName", "Joe"),
new XElement("LastName", "Rattz")),
new XElement("BookParticipant",
new XAttribute("type", "Editor"),
new XElement("FirstName", "Ewan"),
new XElement("LastName", "Buckingham"))));
IEnumerable<XElement> elements = xDocument.Element("BookParticipants").Descendants("FirstName");
// First, I will display the source elements.
foreach (XElement element in elements)
{
Console.WriteLine("Source element: {0} : value = {1}",
element.Name, element.Value);
}
// Now, I will display the ancestor elements for each source element.
foreach (XElement element in elements.Ancestors())
{
Console.WriteLine("Ancestor element: {0}", element.Name);
}
// Now, I will display the ancestor elements for each source element.
foreach (XElement element in elements.Ancestors("BookParticipant"))
{
Console.WriteLine("Ancestor element: {0}", element.Name);
}
}
//-- AncestorsAndSelf
private static void AncestorsAndSelf()
{
XDocument xDocument = new XDocument(
new XElement("BookParticipants",
new XElement("BookParticipant",
new XAttribute("type", "Author"),
new XElement("FirstName", "Joe"),
new XElement("LastName", "Rattz")),
new XElement("BookParticipant",
new XAttribute("type", "Editor"),
new XElement("FirstName", "Ewan"),
new XElement("LastName", "Buckingham"))));
IEnumerable<XElement> elements =
xDocument.Element("BookParticipants").Descendants("FirstName");
// First, I will display the source elements.
foreach (XElement element in elements)
{
Console.WriteLine("Source element: {0} : value = {1}",
element.Name, element.Value);
}
// Now, I will display the ancestor elements for each source element.
foreach (XElement element in elements.AncestorsAndSelf())
{
Console.WriteLine("Ancestor element: {0}", element.Name);
}
// Now, I will display the ancestor elements for each source element.
foreach (XElement element in elements.AncestorsAndSelf("BookParticipant"))
{
Console.WriteLine("Ancestor element: {0}", element.Name);
}
}
//-- Sort Smaple
private static void SortSample()
{
XElement root = XElement.Load("Data.xml");
IEnumerable<decimal> prices =
from el in root.Elements("Data")
let price = (decimal)el.Element("Price")
orderby price
select price;
foreach (decimal el in prices)
Console.WriteLine(el);
}
//-- Find an Element with a Specific Child
private static void FindElementwithSpecificChild()
{
XElement root = XElement.Load("data.xml");
IEnumerable<XElement> tests =
from el in root.Elements("Data")
where (int)el.Element("Quantity") > 3
select el;
foreach (XElement el in tests)
Console.WriteLine((string)el.Attribute("TestId");
}
}
}
}
http://msdn.microsoft.com/en-us/library/bb387053.aspx
http://msdn.microsoft.com/en-us/library/bb387053.aspx
7.25--> A 3 24.50 B 1 89.99 A 5 4.95 A 3 66.00 B 10 .99 A 15 29.00 B 8 6.99
7.25--> A 3 24.50 B 1 89.99 A 5 4.95 A 3 66.00 B 10 .99 A 15 29.00 B 8 6.99
回答by ctb
The answers are in this thread...you just have to do a lot of sorting to find them, so I've done the work of compliling them for you:
答案就在这个线程中......你只需要进行大量排序才能找到它们，所以我已经为你完成了编译它们的工作：
- YES you can edit elements
- Deleting elements is easy: element.Remove(); (Remember to save the xDocument after that)
- 是的，您可以编辑元素
- 删除元素很容易： element.Remove(); （记得在那之后保存 xDocument）
Now if you're reading this thread, you probably want to know HOW to edit elements. There are two different ways that data is stored in xml, e.g.:
现在，如果您正在阅读此主题，您可能想知道如何编辑元素。有两种不同的方式将数据存储在 xml 中，例如：
<tagName attributeName="some value">another value</tagName>
- As an ATTRIBUTE on a tag
- As the content (read value) of the tag
- 作为标签上的属性
- 作为标签的内容（读取值）
To edit the value of an attribute, knox answered his own question:
要编辑属性的值，knox 回答了他自己的问题：
d.Descendants("record").Where(x => x.Attribute("id").Value == "2").Single().SetAttributeValue("info", "new sample info");
In other words, get the XElement that you want to alter, and call element.SetAttributeValue("AttributeName", "new value for the attribute")
换句话说，获取要更改的 XElement，然后调用 element.SetAttributeValue("AttributeName", "new value for the attribute")
if you want to edit the value or contentsof a tag, then Ajay answered it (if you dig through all his code):
如果您想编辑标签的值或内容，那么 Ajay 会回答它（如果您仔细阅读他的所有代码）：
persondata.Element("City").Value = txtCity.Text;
Or, in other words, once you have the XElement you're after, just use .Value and assign away.
或者，换句话说，一旦您拥有了您想要的 XElement，只需使用 .Value 并赋值即可。
Remember that after you perform any of these modifications on the elements in memory, you've got to call .Save() on the XDocument if you want to persist those changes to disk.
请记住，在对内存中的元素执行任何这些修改后，如果要将这些更改保留到磁盘，则必须在 XDocument 上调用 .Save()。
